Well, those issues are mostly solved by changing Perish Song in Thunder Wave, I guess. Nothing not named Sableye is fast enough to Taunt Celebi after being paralyzed. Perish Song was intended to have an additional answer to Cube, however if everyone agrees that it makes us much more vulnerable to counterpicks and Thunder Wave is the way to solve this problem, I'll edit my submission immediately. The Scizor weakness is unavoidable if we choose Celebi, but many of the other proposals have the same problem, and tbh, worrying too much about Scizor when we have both Keldeo and Heatran is an exaggeration, at least to me.
However, I don't really agree on this "hate" towards defensive pokemons: do you think we should avoid defensive picks at all costs? What if a defensive pick covers most of (or everything, like Deo-D the last time) the oposing team? Are we better to delay all the defensive picks for later to ensure putting enough pressure on Team 1? I don't think so. Picking all the powerhouses now and "be forced" to either go all out offensive or to pick defensive things later is a disadvantage since they can pick a solid defensive core to stop our "early-chosen" offensive pokemons. Of all the defensive picks we can do now, Celebi offers flexibility in the form of status absorption and U-Turning / BPass, and this should make sure that with proper prediction it doesn't become set-up bait. It also stops everything in Team 1 and may become difficult to switch into if we give it T-Wave. I don't really see how this is a bad pick, even if it doesn't put a big offensive pressure on the other team.
Not saying that we should pick Celebi at all costs, your Abomasnow pick is interesting (although I don't like it), but we should be a little more open minded towards defensive things, at least IMHO.