In regards to comparing strategy at what Cataclysm RBGS were (What I am most accustomed towards) versus Free to Play premades:
Numbers: How much damage or healing certain classes can produce.
and
Mechanics: What spells or abilities certain classes have available for themselves.
Now in regards to numbers, they are not so fundamentally dissimilar as to prevent any comparisons from being made. Certainly, in 5.4 hunters and rogues are capable of far more damage relative to health bar size (I.E., an ambush for 60% of a geared healer's health is unique to our bracket in this comparison). Therefore, using numbers from 5.2 allows for a more accurate comparison to be made.
In regards to mechanics, there is certainly an extremely large difference. However, I do not believe this difference prevents strategies from emerging similar to those of Cataclysm RBGs.
Melee Classes, in Cata, were almost non-existent in max level RBGS - with 2 exceptions. Rogues were able to be mobile and defensive enough by their own merit to keep up with the extremely heavy AoE DoT cleaves. Death Knights, also, were able to use their cooldowns to prevent damage taken while at the same time potentially guaranteeing a kill with death grip.
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Back to Free to Play: Rogues through stealth, evasion, and intelligent play should be fine in almost all scenarios in Premade team-fights. There may be some exceptions to where a boomkin and an ele shaman turn and unload their max damage spells into them, but otherwise they should be able to deal damage and kick casts while still being in safe range of their healers.
Arms warriors, however, present a meta-shift. There are no pulls, at least for which Free to Plays can use. This presents a problem, since in a competitive game there won't be any enemies to use as an "intervene" to your healers. By charging in, you give the enemy team an extremely easy target to swap to. In regards to the statements regarding Arms being easy to kill, I agree with this.
So then for a team that wants to utilize the extremely powerful ADDITIVE mortal strike + Battle Fatigue, what should they do? Completely forgo this buff that could almost single-handedly win teamfights for them? I think the answer is in the playstyle of the group to accommodate their warrior.
When playing with a warrior, groups should push into the enemy team, instead of using a ranged-vs-ranged "skirmish" kind of mentality. By narrowing the gap between your team and the enemy team, you allow for your spells to be cast on the enemy healers (if need be), while allowing your healers to be within range to comfortably heal anyone. The warrior WILL be a focus target by nature of being a warrior, so healers should be aware of that (Extremely similar to how healers were extra attentive to the health of their Unholy Death Knights in Cataclysm RBGS). By removing much of the distance between teams, Warriors can prosper without becoming a burden while constantly being dead. Additionally, CC classes like warlocks and mages will have many more options as targets to lock down.
Just some thoughts in regards to shifting the meta.
Tl;Dr -
1. There are similarities between max level Cata RBGs and F2P premades
2. Teams using Arms warriors should push up as far as possible against the enemy team, to allow healers more lee-way to heal the warrior, and to give him more room to kite back if he is being focused too intensely.