Spamfest[*] While it is true that at high levels of play it won't matter as much because everyone will have great uber tracking/damage calls, and that it is not a true substitute for uber tracking, it still only gets rid of situations where that skill expression exists while adding no new interesting decisions/strategies to the game.
I mean, from what I can see, even at the highest levels it fucks around with uber tracking. The solemn vow is a "must-run" tier weapon, in the same vein as the crossbow and escape plan. The thing about uber tracking is that it assumes your opponent is building properly. With the solemn vow, you no longer have to worry about that variable. You now should always know if you have ad, even, or disad. Sure, the meds need to have line of sight on each other, but that happens organically often enough that it will be a factor. I see us having some fucking weirdo situations where we have teams trying to make room for their med to peek, trying to make sure they still have ad before pushing.
I also think it's unfortunate that teams will also no longer make the mistake of pushing when they think they have ad, but don't, since the other team built more efficiently. In my brain, changing the game so that teams no longer make mistakes like that is going to contribute to more stalemates.