Last time i played this game some of the most unfortunenate problems for mythic plus were:
You had to raid cutting edge and farm it in order to climb top ratings in mythic plus because there were no other way to have a best in slot item set. Mythic plus only players were forced to be disadvantaged in gear.
It was impossible to catch up in gear and be completitive if you started mid season and missed a few vaults. You basically had to wait for next season and take a week off from work (or maybe two weeks).
You had to play have a 5/5 premade group and play all day all night together because if you have a new guy in and miss a top key because he’s new to stuff that you’re already practiced before, you miss too big chance and it’d be frustrating. There were a possibility that you won’t get that key for days after.
There is no matchmaking at all so you had to apply to other groups for hours and finish some days without even going into a key because no one wants to risk a key without their 5/5 premade or without some people completely overqualified for the key.
You have to play 4-5 alts and do 8/8 vaults per week with every single one of them on top of your main because meta can shift anytime and if you don’t have a full gear alt that fits in meta, you wouldn’t get to play rest of the season.
Any improvements yet? Is it still the same for months and years now?
There are characters at the top that exclusively have gear from dungeons. But there are a lot of ways to get the loot you want from raids, rather easily, even outside of raids. But that loot will be Heroic and the upgrade ceiling will be lower than Mythic obviously. The difference will help of course.
Catch-up when it comes to gearing is really good right now. A fresh alt for me now for example can get fully geared 285+ within a day by doing M+ only, but finding groups without a main rating will slow that process down of course.
Full premade VS pugging will always be the best way. It’s about teamwork, and getting to know your partners and their playstyle patterns will always be a huge advantage.
Of course there are no Matchmaking, because of the reason mentioned above. It has been proven time and time again that once someone can “queue into something” they wont care as much, and that’s devastating at high levels.
Currently it feels like any spec can do good, but if you live the pugging-life, of course you will have a hard time if you decide to play something considered not to be meta. That will always be the case if you want to reach the top. All the advantages are important, and disadvantages are considered handicaps at that point because of the level of min/maxing.
You can however control if this will be a problem for you. Don’t aim too high for your skill/dedication, get friends with similar skill & goals to avoid LFG/pugging entirely, “gitgud”. Or embrace LFG by playing meta. As stated above; gearing a new character to be push-ready is fast now, so you dont really have to upkeep characters that aint meta if you want to be a meta-player. Hard-swap early during the patches if the changes are drastic enough.