I know what you're saying, Minscandboo. In a perfect world, conditions would be such that you'd never disengage from a mob for hours worth of fighing, nor would any other factors affect the steady in-sync count-down of your ja timers to the count-up of your TP. However, the game's just not like that. It took people awhile to realize the "get 100tp every 30 seconds, sa+ws; do it again, ta+ws" model was unrealistic. It's about being flexible. A single party on thief, where you bear this in mind, and you'll see what I'm talking about. Feather tickle :( = tp wiped. Or, your ja timer is ready and your tp is at 99%, but the mob dies. And another mob doesn't spawn or come to camp for 30 seconds. Sa/Ta merits adjust your ja timers. And further, in ideal situations, 30 seconds to get TP is actually rather slow. Assuming the right conditions, I think I'm at about the 18-20 second mark in exp. Also, there's the matter of prepping sa/ta before a fight to do more damage. One could go on an don. You prolly already understand what I mean, but this is just reinforcement, hehe.
As for Denali vs Turban for solo, let's say,
Premise: There is a solo/tanking situation in which marginal 5 evasion > 1% haste
Premise: Denali Bonnet comes with 5 evasion more than turban; turban 1% haste more than denali
Premise: These are the only relevant stats on these pieces we're concerned about for this comparison
Conclusion: There is a situation in which denali > turban
The only thing in question would be the first premise. But I'm pretty sure it's true. So the only thing that matters is using denali in that or those situations, and not others. This is why we build more than one set for soloing or tanking, same as with damage-focused builds.