Im fairly close to fully modded out in 72 armor/mod/enhancements.
There is a *massive* difference between being fully modded out in *good* mods/enhs (i.e. the stuff that drops in FPs and Ops; often the good mod/enh only comes on 1-2 pieces of gear, to boot) and being fully modded out in *bad* mods/enhs (i.e. the stuff you buy with comms).
Comm gear is pretty much *universally* high End and painfully low Endurance for tanks. Token and drop gear are the actual high mitigation options. If you're packing HP in the 40k+ region, it's because you're stacking Endurance via comm gear and/or using Endurance augs. *Both* of those things are bad.
I was running a pug Ops last night and the other randoms I was with thought that the other tank they grabbed, who had 8k more hp than me, was better geared based purely upon his hp. Of course, they completely missed the fact that my DR was 1.5% higher, Defense chance was 3% higher, Shield chance was 5% higher, and Absorb was 5% higher.
High hp for a tank is, like it's always been, just a bad tank's way of demonstrating their epeen. A good tank is only going to have marginally more hp than a DPS because *real* tanking is about mitigation, not hp.