No, I'm playing a game right now called Faster Than Light which is amazing! Random scenarios occur that I need to react to, even with a pause button the random elements make it exciting, multiple play-throughs have all been great. Right now FFXIV is almost completely scripted, that'll get boring much faster than if a fight introduced random elements that you need to react to.
And before you say it:
I think you're forgetting a key other point the OP mentioned though, that the random effects you need to dodge are not insta-kill mechanics.
What's that mean? Well if you're a DPS with good gear, or a good healer, you can compensate for their screw up. This may motivate you to get better gear or try harder for that gear because you know it may turn around a fight, saving you and your friends time, a huge benefit I believe. Right now, there are some mechanics (not all) , where you can only watch helplessly as they get knocked out of action completely, from which the remaining party is unlikely to recover from. If the developers placed less emphasis on mechanics, then with good enough gear and skill the rest of the party should be able to compensate and win more easily - it's all about balance.
This brings us back to a very important point, IF gear was made more relevant, that would be an additional reason for players to beat the bosses, other than the hurrah of winning and adrenaline rush, which I can find in any multiplayer game. Even many multiplayer (non-MMO) games have rewards that improve your win-rate.
But currently in FFXIV, as the OP mentioned, there are too many mechanics that make gear completely irrelevant, if Leeroy in T5 forgets to dodge divebomb and knocks everyone into the purple fire it's an insta-wipe. What if with good enough gear that fire could be resisted up to 50% damage, the guy who screws up dies but everyone else who has good enough resist gear gets taken down to 2k HP, if healers are on the ball they may be able to get the tank back up fast then aoe cure the rest. I would take this implementation over an echo buff any day! At least when someone screws up there is some chance, even if it's 5% and with good gear 10% chance we could recover -not 0%.
And when T5 first is released, nobody should have resist gear high enough to survive this mechanic, but later on absolutely! Why shouldn't I be able to in 2 months from now, take my friend who just started into T5, with my superior gear and help him carry it? I want him to catch up to 3rd coil or whatever the current content is anyways, with the status quo even 5 months from now there will still be people who can't get this mechanic down 100% and it only takes 1 out of 8 to kill everyone.
Mechanics are awesome, they just need to be less debilitating, for "mainstream" players, a term which the OP coined, sometimes you'll have fun, other times it may be frustrating when someone screws up and causes the whole party to wipe. Right now that's all there is, but what if you could lick your wounds, and try to beat some other quests and get some other better weapon then go back and try again, except this time when someone screws up, your 10% extra healing wand is able to salvage the fight? Right now, in some fights, not all, it's not possible. Titan EX and T5 is the main example for now.