Team duskie without a Dusknoir, I was dissapointed lol, anyway moving on. I like lead Heatran, you obviously know what you are doing with it and it works well, the best are the simplist sometimes, the least can go wrong lol. I imagine lead tar can give you a bit of worry, seeing as Scizor is your only "real" switch into it. I wonder how useful Skymin is on your team, and whether the "SubSeed" set would allow you to work better, that would allow you to play with CB Tar a bit more. You can go out on the predicted EQ and set up a Substitute and Stall, flinching and Seed Flaring as nessecary, you already have pretty reasonable coverage for Heatran and I'm not really sure where else Earth Power would be useful, if will mean that only "two" members of your team are Blissey weka rather than "three" (Yes I know Heatran can explode, but thats quite a large sacrifice really + theres at least a chance of Protect)
Is there anything that Hydro Pump hits specifically? If not you might want to change it to will-o-Wisp as a Pseudo check against Lucario, who will have a bit of a run at your team if you are unprepared. Yes Crunch varient will go straight through Rotom but it can survive Ice Punches to Will-o-Wisp back, as you will agree once SD luke sets up only clever switching will win you the game. CBTar gives it a nice opportunity to set up also. Discharge on Rotom might also be a good idea for the extra paralysis which might come in useful to stop things like Vaporeon wish Protect self healing or something along those lines, just a sort of "just in case" as you are running a defensive set anyway. If Hyrdo Pump isn't nessecary you could also try ResTalk Zapdos who will do better against Lucario, especially if you EV it to outspeed it, with Rest and Sleep Talk ZApdos can stall better thanks to its Pressure ability, just a thought to consider.
Not much else I noticed as I maintain with well tested ladder teams that have been succesful, changin actualy pokemon may ruin the synergy of the team too much, Zapdos / Rotom are similar up to an extent, but this team doesn't need a whole lot doing to it really. Congratulations and I hope some of this helped =D