Yet the last boss drops gear 2 tiers higher. I know it's doable, but has it officially been stated as the case? EV HM is rated for columi too correct? Is EV HM and TFB SM the same difficulty? And just out of curiosity, have you personally ever ran TFB SM with a full group wearing nothing higher than columi?
Actually it has
been explicitly stated that TFB SM (and obviously EC SM) are balanced for Columi geared players. I'll admit I haven't tried it in a full Columi group since my guild was way past that gear-wise when TFB released, but yeah I think a group who knew the strats and were good on their characters would do fine. And I've certainly seen low-geared alts make it through the place with no problems.
And while EV HM and TFB SM are not the same difficultly, it's not because TFB has shorter enrage timers - the difference in difficulty is almost entirely mechanics-based. When pugging I'd MUCH rather take someone on an undergeared alt who knew the fights in and out than someone with full BH who is bad. TFB is like Lost Island in that gear level doesn't have a huge impact in how quickly or easily you down the thing.