At least as far as being able to see uber %s goes, doesn't it just shift medic skill to 'actually building ubers' instead of just guessing them? since you don't have a spy to call uber %s you just assume they're building optimally but you never actually know, meaning that there are probably tons of cases of sub-optimal building going unpunished because there's no way to know and it's not worth basing a push around the assumption that your opponents are bad. while 'guessing/knowing enemy uber %s' based off of time may not be as necessary, i'd argue that it's more important to emphasize actual, tangible, skills (building ubers quickly) than making educated guesses, especially when those guesses do more to mask bad play than highlight good play. it also results in teams gaining more actionable information, increasing the pace of the game because these cases of suboptimal building are now actually pushable.
and while i don't think balancing around lower divs is an ideal strategy, i'd imagine less experienced medics will be able to improve more quickly if they consistently see feedback regarding their/their opponent's building