Aside from Gliscor, none of them have Taunt, and ALL of them will be shut down by Taunt from a faster pokemon. I am not saying these leads are worse, but they are different. Floatzel is also the only pokemon that can baton pass Bulk Up boosts, aside from Smeargle and Blaziken I think.
Floatzel will be shut down by anything attacking it, is the flawed logic here. You're assuming Floatzel is a one-and-done Pokemon as well with Focus Sash, and thus probably a lead. That's a waste of team space, unless you're considering using it on a Baton Pass chain (which has its own issues).
And since you mentioned leads.. These are the 15 Most Common Leads Last Month in OU:
| 1 | Azelf - Speed tie, loses to Psychic/Thunderbolt/Grass Knot.
| 2 | Metagross - Dies to Earthquake+Bullet Punch
| 3 | Swampert - Dies to Earthquake, but can't stop the pass.
| 4 | Jirachi - Loses to almost every varient.
| 5 | Aerodactyl - Aqua Jet will do 42.4% - 50.3% (assume 4HP/0Def), so if Aerodactyl attacks first, you lose nine times out of ten. If it Taunts, it will still get SR up, and likely a large hit on Floatzel.
| 6 | Infernape - Fake Out+Close Combat with Focus Sash wins. Can't win against Fake Out-less versions either, because against 64 HP/0 Def Infernape, Aqua Jet does 41% - 49.1%. Oops.
| 7 | Roserade - Dies to STAB Grass if it Taunts, if not, Roserade has Spikes up.
| 8 | Heatran - Aqua Jet will do 26.5% - 32.1% to a Heatran with 4HP/0Def investment. Floatzel loses.
| 9 | Tyranitar - Aqua Jet does 20% - 23.9% against LeadTar. Annihilated by Crunch, Stone Edge, Counter. Loses Focus Sash to Sandstream.
| 10 | Gliscor - Aqua Jet, 18.6% - 22.6%.
| 11 | Smeargle - Taunt will shut down most Smeargle, but if it's carrying a Scarf you're in trouble. Aqua Jet does 39.7% - 46.8% to 252 HP/0Def, so you can't 2HKO.
| 12 | Ninjask - Aqua Jet does 27.4% - 32.6% to 176 HP/0 Def. Taunt will shut him down, but you can't prevent a single speed pass.
| 13 | Hippowdon - Super Effective! 14.8% - 17.6% Aqua Jet. Bulk Up first, then pass straight away. Floatzel does well here.
| 14 | Dragonite - Draco Meteor/Outrage/Dragon Claw/Earthquake+Extreme Speed will take care of Floatzel.
| 15 | Bronzong - Floatzel defeats Bronzong well. Taunt shuts him down, while standard Earthquake/Gyro Ball won't do over 30% maximum.
So, basically, Floatzel can manage to Baton Pass once with Focus Sash. He doesn't have time to Taunt 90% of the time, because if he does, and they attack, you don't pass anything. There are many Pokemon that achieve this. Aqua Jet is not powerful enough to warrant its use on a base 115 speed Pokemon, where Waterfall would actually threaten something like Heatran (sometimes).
Like said, Floatzel is a poor choice in OU, given the current circumstances, and there are much better leads for 'chains'. And of course.. this is not Creative at all. It's already be discussed at length, and is even in the analysis (with a better EV spread)! See Kristy:
http://www.smogon.com/dp/pokemon/floatzel