Got farther in the game now, and I can see why Rotom bothers some people. It talks a lot, and it's mostly the same handful of advice so you see the same messages all the time. It literally speaks after almost every time I do something at this point. And on top of that, you can't make use of any of it's other functions or engage in any other interactions with it until it's done. It's probably annoying as all hell for some people. People shouldn't have to choose between not having Rotom talking too much for them and not engaging in what makes it fun.
But, how much Rotom talks doesn't really bother me personally. The frequency of its speech began to rise exponentially for me around the time of the fire trial, and I'm now about to set off for Poni Island, so it's been a chatterbox for quite a while now, so if it was going to be an issue for me, it would've been so by now. I like Rotom in US/UM since it now has what it lacked in S/M--it's interactive and feels like a real partner to have along and has multiple useful functions rather than just being a map that talked sometimes, which is basically what it was in S/M.
Also.....did anybody here let Rotom call them "Master"? It asked me that yesterday and I refused to let it do that. It's like a) that's not our relationship and that's not going to be our relationship, ever, and b) I'm not worthy of being called Master by anyone in any manner. I'll just stick with Roto-N thanks.