In the early days, by which I mean about Fallen Empires-era Magic: the Gathering and the slew of new games that were coming out every week, this didn't matter much. Nobody of an age to play had the money to buy the cards for a perfect deck, and we were perfectly happy to play with whatever random cards we got in our packs and construct imaginary decks in our head or, less often, using proxies. It was also in the day when you could really squeeze every single fucking card into a single issue of InQuest, errata was seldom heard of, and pretty much everything was "legal" because none of us did any of those tournament rules and damn few of us tried out any of the variants rules that cropped up from time to time.
Even by these rather generous standards, I was shit.
It's not that I couldn't tell you whether a card was good or not, or that I couldn't see deck-building strategies and things, but my heart was never in it to make a tactical deck, nor did I have the money to pour into it. The problem is that a lot of the strong deck ideas were often obvious or common, while I was always attracted to...marginal cases. Sometimes this was an obscure concept, like the bloody stupid Red Control deck, but more often it was themes that destroyed me. Because I like storylines, and some small part of my brain that should know better has this unspoken idea that things that are lumped together by the same name or key word or something should maybe actually work well together.
It's an issue, I admit: you do not just build a good goblin deck by putting all the goblin cards together in a single deck. That deck will be shit, because not all the goblin cards are good cards, and for some of them to work right you're going to need other cards. It's card strategies and integrated mechanics that make for a killer deck, and sometimes there's a theme component to that and often there is not. Then I go and build the deck and lose anyway.
The case in point, for the Legacy of the Five Rings card game, is that I've dug out my old Hare Clan deck. This was a truly shitty deck, but I liked the Hare. They were a minor clan among minor clans, and they very often got the short end of the stick. A lot of their cards aren't great, and a great many of them don't really go together, because there's no common mechanic. Hell, the major special power of the Stronghold (Shiro Usagi) is that your Hare Clan personalities and followers actually are considered members of your clan, so you don't pay a premium and they're not considered unaligned ronin. They're not generally considered a competitive side is what I'm getting at, and I didn't really help that reputation even in my informal games.
L5R has been around a long time, and it has produced many broken cards. It has changed the rules. It has even changed the card backs, because the International Olympic Committee are a bag of dicks.

Left, original; right, current.
So for tournaments and the like, there are different plays formats. Strict Jade, Extended Jade, Emperor, Samurai, Ivory, Open - these are the official formats for the game, an the fans themselves have a fucking committee set up for a fan-made format called Legacy. They did this because, well, some cards aren't allowed in some formats. This makes more sense than it seems, because there are a bunch of mechanics that aren't used in the latest editions, and a bunch of broken cards for older editions, and the perennial "if I combine this card from this set with this card from this set, I basically gain infinite power and win the game."
I'm pretty sure my Hare Clan deck didn't fall into any of the official formats. This is pretty much because the idea of a Hare Clan Deck did occur to the gamemakers at some point - there wouldn't be a Stronghold if it didn't - but it's also quite obvious that a lot of the cards were from very different sets over a long period of time, and my general approach to deck building didn't help out. See, my basic concept was that if the only advantage of the Hare Clan was that they were a clan, then I should include all the cards that reinforce the benefits of sharing clan alignments and family names. So, a bunch of cards that take on the clan alignment, items like Clan Banner, Clan Standard, and Family Sword; holdings like Seat of Power, etc. I even bought up a bunch of stuff that even if it wasn't a mechanical fit was a thematic fit - Clan Estate, Family Dojo, Legacy of My Ancestors, etc. And a shitload of strategies (Arranged Marriage, A Clan United, Purging the House, Cross-Clan Wedding, etc.), events (Creating the Monkey Clan, Open Recruitment), what-have-you.
Believe it or not, that's not enough to fill a deck. Likewise, it's not enough to build a functional deck. You need a certain number of holdings, preferably ones that you can afford to bring into play and do shit when they get into play. You need armies you can bring into play to fend off attacks from other players, and make your own attacks. You need to consider the benefits and drawbacks of magic, politics, duels, and attacks from other players. You need, above all, a strategy of how your deck is supposed to work; a random collection of farms, mines, and samurai is sadly probably not going to cut the mustard.
There are some things you can do with the Hare Clan concept, and I did them. They're just not very good. You can raise armies, but not as fast or as big as other players. You can gain honor, but again not as fast or as big as other players. You can do quite a lot with equipment and little bonus tokens and passing them from one personality to the next, if you have the right cards set up, and it's probably the strongest point my point had, but it's not unique to the Hare Clan, it just takes advantage of some cards like Clan Heirloom and Daimyo's Gift that can make it easier to pass stuff between clan members. But it's not really a competitive edge over other decks...and then there are the drawbacks.
Magic is almost nonexistent; the Hare Clan has one shugenja (water). Politcs is completely nonexistent, there are no Hare Clan courtiers. Duels are also pretty much out, unless you have your best personalities with your best equipment, and even then there are plenty of times they're going to lose.
I did experiment with allied decks. That is, y'know, there are cards which will turn your unaligned/gaijin/nonhuman/etc. cards into your clan alignment. Which is good, if you can pull it off, because generally speaking the ratlings, gaijin, naga, and whatever have much better cards than your basic Hare Clan. Hell, most of the ronin are better than your bushi by a long shot. I still never actually won a game when I tried that, but mainly it was an issue of timing in that I couldn't get a proper balance between the shitty Hare deck and the shitty Other deck I was trying to use to complement it.
I never really tried doing a Hare/Shadowlands deck. Thematic reasons aside, swallowing the Honor loss of using Shadowlands cards is a pain if you're not built for it from the ground-up, and the Hare (deficient in magic and politics as they are), just aren't built for it - and even if you did decide to go that route, you're stuck with what is essentially a limited and crippled Shadowlands deck which can probably never get above water on Honor. The closest I ever came was toying with some undead concepts - you can do some crazy shit with Burial Mounds - but I never tried it in play.
I mention all this because the Creatures of Rokugan review (we'll finish it someday, I promise!) had me digging out my old Hare Clan deck again, and even buy a couple boosters of the latest set to see what the cards looked like. I thought I was cured, but it seems it was just a period of remission; whether or not this flare-up will last long and painfully or not, I have no idea. But part of me would kind of like to refine my silly old theme deck, even if I never play with it again.