You're mostly right and, indeed, we mostly remember those monster performances of his against Monaco, when he played on the right wing. In serie A he was hardly a protagonist (started only 15 matches) and he had some shocking performances. For good 6-7 months he looked finished as a professional.
On the other hand, it still remains that he was our best rated player in CL and our most potent player in regards to goals+assists. Almost as if he cared only about that particular competition.
Now, it stands that at 34 he probably wouldn't have been so important this year, and, hopefully, those wingers we bought can replicate his numbers or contribution in CL. But what also stands is that we are weak on the right defensive side of the pitch. With Alves' departure we lost experience and, since he probably won't replicate his last year's performances in CL, maybe we didn't lose much more. But, however we put it or spin it, we can't say that we are as good as we were on the RB position, and we surely can't say that we're better. Hell, if we accept that Alves wasn't that important, it looks even worse for our board that they failed to replace him with something better.