For some reason, none of the cards with clan abilities are multicolored.
What this means is that each clan has easy access to all five abilities, although not necessarily the best examples of an ability. Sure, I can use [card]Heir of the Wilds[/card] or [card]Riverwheel Aerialist[/card] in my Sultai deck, but will they be as good as they would be in a Temur or Jeskai deck? Actually, maybe even better. Sometimes.
Sultai is a more controllish combination of colors. Sure, it can be built to be a more tempoish deck, but mostly you want to sit back, stabilize the board and put yourself in a situation where you can put your nicely constructed graveyard into a good use. In this sense [card]Heir of the Wilds[/card] is a great card. It can trade with pretty much anything and can be a good beatdown card if you happen to need to go down that path. Sure, if you have ferocious, it would better (and key Sultai creatures tend to have three Power).
[card]Riverwheel Aerialists[/card] on the other hand is a good finisher for a control deck. The Prowess is nice bonus, but the card works just fine without it. There aren’t many cards that can blank it in the air. And Sultai has plenty of noncreature goodness to trigger the Prowess if need be.
But from a flavor standpoint this is a bit problematic. Clans don’t get to show of their abilities as much, when any clan can abuse any mechanic. I get why this is possible (because of limited, where you need enough options for every deck, so that no one is forced into a corner in a draft, and it can limit the variance at least somewhat in sealed).
This is someone mitigated by cards in clan colors which facilitate or abuse the clan mechanics, but these are generally rare or even mythic. These include the clan leaders, Ascendancies, Charms (which generally have one mode that playes well with the clan mechanic) and several other tricolored cards.
Abzan has [card]Ivorytusk Fortress[/card] to keep you creatures either attacking or outlasting without compromising your defenses, and [card]Armament Corps[/card] to give those important +1/+1 counters to creatures that can’t naturally gain them. Jeskai has [card]Sage of the Inward Eye[/card] to gain extra benefit from all those noncreature spells and [card]Warden of the Eye[/card] to play those spells twice. Sultai has [card]Rakshasa Vizier[/card] to grow into immense sizes (you know, [card]Become Immense[/card] permanently) from delving and [card]Sultai Soothsayer[/card] to put cards into your graveyard. Mardu doesn’t have anything as direct, but [card]Ankle Shanker[/card] does make attacking (and thus triggering Raid) easier. Temur… well, Temur doesn’t really have anything. Sure, they do have plenty of creatures with Power 4 or better, but so does Abzan.
These gold cards do help somewhat with the flavor, but they are still not readily available due to rarity in limited. The usual strategy of either limiting yourself to two colors, or going over and playing four or five in limited makes the flavor that much more hard to feel. Perhaps there’s too much fixing in the format.
From development point of view, the game works nicely. You have plenty of options on how to make your deck and there doesn’t seem to be a strategy you need to use to be able to be competitive. Abzan is very strong, but since that usually means more than one player will go into black-white, its not that devastating. From flavor point, not so much. Flavor-wise its pretty messy. Abzan and Mardu seem to be very different approaches philosophically, but they work very well together in the warrior-style deck.