I disagree with 20 man being easier. If you have to make it flex, I'd say that it's possible that they'll quite easily end up in the position that they need to restrict certain mechanics too much, can't make mechanics that caters to the raid having a specific class, and they can end up having to restrict which mechanics they implement based on it needs to be possible to be handled on all raid sizes.
When you can't be certain on the amount of people participating in a fight, you need to in some way make it doable for all the possible raid sizes. And I can't see how they'll do that without making it easier or restrict mechanics. Else we'll just have it "flex" but we'll end up once again in 1 raid size being optimal or maybe even the only doable size, so it would being the same as now. I think tho that the former would be what would be most likely.
IMO what could be a good idea:
- Merge servers to make servers have a large enough player base.
- Remove LFR, i know this is not the most popular idea amongst some people, but imo it doesn't prepare people for raiding and doesn't give a prober feeling of what raiding is.
- If need be add a extra difficulty for flex, above heroic raiding to make sure those people have content even tho they can't do mythic (This idea i'm not certain of since one of the major issues atm is the amount of difficulties and the way that adds to item inflation and the crazy increase in ilevel we'll get across a expansion. - Them crazy numbers)
- If we don't add another difficulty above heroic, for flex, then in some way keep old content worthwhile for a longer periode of time (that HM wasn't worthwhile doing as soon as BRF came out was really sad imo)