It kind of depends on what you are planning to accomplish in the next 2-3 months. Do you intend on being on the forefront of Alexander Savage when it comes out in ~3 weeks? If so then I would not go MCH. However, if you don't mind waiting a while to experience those fights and if you really like MCH and the fundamentals of the job (lower DPS than a melee, support for TP/MP regen, ranged and mobile attacks which may be switched to immobile with Gauss Barrel) really call out to you, I'd go MCH. I have ran all of the 50-60 dungeons with a MCH and have never seen one kicked from their party. Does it happen? Probably but it's not nearly as rampant as a lot would have you believe. Right now, though, MCH will probably have problems getting into the EX Primals for Bismarck and Ravana but those fights are also new and don't have nearly as many parties striving for clears right now. As that paradigm shifts, MCHs may have an easier time joining... I just wouldn't expect to ever be allowed to get into a party which already has 1 MCH or a BRD.

For the most part SE did a great job over the course of ARR keeping the jobs in line and competitive with one another. It'll just take time for them to buff BRD and MCH while they determine how they want to handle the buffs to bring them in line without overpowering them. Also keep in mind that BRD/MCH might be absolutely necessary in Alexander Savage even though they don't have as high of DPS. BRD never had as high of DPS in ARR as the other jobs after they got nerfed in the early days but a BRD spot was pretty much a staple of every endgame progression party. If the need for TP/MP regen is that great, then BRD and MCH will still have a spot in the top tier raids, even if they don't get buffed. If they are so bad that they don't have a place in endgame then they will get a buff within the next couple of months pretty much guaranteed.