Originally Posted by
eschatological
The problem is, TOTH can and does overwrite itself. Plus, you may munch charges just because you need to CoS to keep SrS up. Plus numerous other things. The GCD-lock problem isn't in the 15s of the proc, but the 10s ICD of LnL. It is damn easy to proc a LnL, proc TOTH, have to fire BA, woops, that zeroed focus, time for a coupla cobras to be above 25 for the next LnL proc, have another LnL proc, oh woops, TOTH buff has already been overwritten by a new one. That's lost procs, and lost damage, and I imagine TOTH is balanced around not munching any AS at all.
Fervor provides on demand focus when you need it, and focus-over-time after that. It is glorious. I love it. I end up firing *more* AS with it than I do with ToTH, as it provides 100 focus every 30s, which is equal to 5 actually used charges of ToTH in that time. Except Fervor lets me choose when I want to be firing those AS.