Thinking of returning; do they require tiered raid progression now?

[Arothand]

Long story short I left the game a little before a month after Mists came out due to a variety of reasons but mostly the (at the time) crazy rep grind and the fact my guild broke apart and had a lot of problems in MSV. I went to Rift when Storm Legion came out and haven't looked back since, but I've considered coming back to WoW, although I'm no fan of the cumbersome grind they added.

Now my question is this: As I understand it for Mists they aren't doing the Wrath/Cata model of a new tier coming out and invalidating the prior tier's gear (not saying that's a bad thing). Would this mean if I came back, I would have to find a... how shall I say... low caliber guild that was still in T14 and clear that before having to guild hop into a guild working on T15? Or is Heroics -> T14 LFR -> T15 LFR enough to prepare you for T15? To put things in perspective when I left the game Heart of Fear/Terrace had just come out into LFR (I didn't run either of them before leaving; I ran the first part of MSV I think twice in LFR, and killed Stone Guard once on normal before the guild had problems and broke up). In short what would be the progression path for someone who left the game shortly after Mists launched and has barely touched T14?

I didn't play during TBC, and in Wrath and Cata of course if you took an extended break you could gear up via badges/points and jump right back into the current tier. With that having changed, is it encouraging guild hopping and using low progress guilds as stepping stones to get into high progress guilds (granted that happened before, but the stories I've heard from TBC state this was a major thing going on then)?

[Seriss]

Depending on how much gear you buy and how lucky you get on drops in LFR, you could theoretically jump into ToT very soon.

Drop rates in 5.0 LFRs are increased, a lot of stuff is available on AH, and if you manage to cap your valor for say 3 weeks, you can buy some ilvl 522 pieces from Shado-Pan assault (1 already at neutral rep, and for friendly rep, you need to do ToT LFR part 1 once and will have access to some more items). Some 476 items are also available from the Kirin'tor, for gold, if I'm not mistaken.

In any case, you'll have a bit of work to do until you're ready for ToT. Maybe hop into a PuG for some T14 raids too and hope for a bit of luck.

[Lithios]

I hit 90 on March 9th. I am ilevel 481 and i have gotten a total of 3 raid drops. One of which is my offspec. You can get the pvp epics, which keep in mind dont penalize you to use in previous expansions, with JP and get decent enough gear for the first tier of raids in under a day. Also the BoE epics from the AH work out pretty well if you have the gold.

[Xenlol]

Grind?

I've played Rift and it was grindy.

All MMOs are grindy, just sometimes in different ways.