Destro wouldn't be a good choice, anyway. It might even be worse than affli actually. The Legion changes made destro MUCH WEAKER in daily heroics (compared to how it was in WoD or MoP)
It now has much slower AoE, much slower Havoc application, much slower (and weaker) Shadowburn casts all of which ensure that destro is now dramatically nerfed vs. trash. At the same time the removal of Backdraft from baseline, removal of Dark Soul, the lessened ability to pool Chaos Bolts, and the lolrng mastery ensure that boss dps is horribly low as well.
In summary, Legion destruction is total crap (in comparison to WoD destro) in current daily heroics. This problem will no doubt be present in "overgeared" content in Legion, as well. It is annoying when they destroy parts of a versatile, nicely functional spec like this