Yes, gemming strength as 2h frost is viable. Bosses will not refuse to take any damage from you after noticing your gem choices.
In fact I would say that gemming strength as 2h frost is optimal for most encounters in this tier, partly because anti magic shell makes sure that you don't need the extra resources that haste would have given you, and partly because of the amount of aoe needed for many encounters in this tier.
Did a Haste vs STR sim a while back, translated into something like an extra 300 DPS on single target (values were 2.68 for STR and 1.7 for Haste). Honestly not worth it because of what Shiira is saying, as soon as you throw downtime and AMS soaking into the mix Haste gemming just doesn't feel as effective not to mention the damage you lose on cleaves.
I don't get it, are you disagreeing or something? I flat out said "gem str" further up the page -.- doesn't mean the difference isn't negligible.
Gemming for haste or strength really is personal preference when it comes to 2h frost, the difference would be like 400odd DPS either way depending on how much movement/downtime/ams absorbing there is during an encounter.
Tbh if you have a dk switching to DW for cleave encounters it begs the question why he doesn't just stay DW?