The reason people are wary about it is because each Kinship costs 8 mana which is a hefty investment and you really want 3 (or 4) of them to get the best benefit since if you're only going to play 2 kinships you might as well just run Rhino Hide and Bear Strength.
On top of that 24+ mana for the kinships you still have to get the creatures out there. For a significantly smaller amount of mana and fewer of your own actions you could have Felella cast Rhino Hide and Bear Strength on you.
The main reason to do kinships is to be immune to dispel and dissolve. I found when I tested this out that you also want to have some equipment and some enchantments to round out your usefulness as a combatant and then you're back to the same old problem of having the stuff you really need be hit with dissolve and dispel.
While it's certainly a fun experience and can hit really hard once your setup is done I think the main issue the archetype has is the huge setup cost in both mana and actions. If you can overcome that hurdle efficiently it could be a really powerful book.
^^ this.
To summarize, 2-4x Kinships is a very slow, mana-intensive start for a melee beatdown strategy. And that's before you even summon the creatures needed to activate the Kinship abilities. You generally can't afford the mana to do a Lair and Kinships, but at least Straywood can quickcast the creatures. Oh, and it didn't really work before Asps because there was no level 1 Reptile before Academy; the bear cubs are nice to have, too.
Anyway, yeah, you're committing a lot of mana and actions to setting it up, and meanwhile your opponent is also gearing up or bringing out big threats of their own, so... it's a neat thing to try, and it can win, and it's different (and some opponents might not be able to deal with it efficiently), but I don't think it's a top-tier strategy.
Regarding additional buffs, because you'll use the Kinships for your primary buffs, you can specialize in just enchantments OR equipment, rather than both. I'd recommend enchantments because Nature. This at least makes all your opponent's Dissolves/Disarms/Explodes useless. But you could go the other way and pack a couple decent melee weapons, Chitin Armor, Packleader's Cowl, Regrowth Belt, etc and make all your opponent's Dispels, etc, useless.
All that said, I don't know much about the current meta, and if there's a lot of conjuration hate out there, or if you run into Altar of Infernia or Idol of Pestilence, then you're going to be in for a tough time.