These cards in particular are going to be the best at avoiding "mis-signaling", because it's more apparent that they have a self-contained function. They are still much more isolated than most other "named" mechanics or features, which can have drafting and other downsides. What if your drafter evaluates Champ as worth it because they expect it to draw 2+ cards on average, but don't really want it for their deck at only 1 card? They want the truly tribal payoff and would rather have picked a better-in-a-vacuum card in that pack if they had known otherwise. Even if it works out in the end, it's an expectation->reality disconnect, which is always unfortunate.
The difference between that and a given example, revolt, is that revolt can be easily supported widely throughout the cube without any pretense at needing it to be self-sufficient. Same goes for most other commonly run mechanics. They integrate seamlessly into a large chunk of the cube/set. Revolt isn't supported by "revolt tribal" in Aether Revolt. It's supported by the fabric of the set involving a lot of permanents sacrificing themselves in various ways, so that it's patently obvious to all but an extremely new player how revolt can be utilized. Same goes for basically any "traditional" mechanic. They might seem disparate compared 1-t0-1, but most of them are intricately supported via other card selections throughout the cube. Like even if you only have 1 double strike creature in your entire cube, you probably have a few equipment, right? Some +1/+1 counters? An aggro deck that wants a 2/2 double striker at face value? Hopefully you can see what I'm getting at. Even the most "isolated" traditional mechanic usually has ingrained support elsewhere, which isn't always the case for tribal mechanics, especially if we are specifically trying to make them stand alone.
This isn't to say I'm trying to pick on the Champ in particular. I do think it's a perfectly serviceable card.
