You want enough spots that you can figure out which of those 15 or so guys will actually turn into something, but yeah, definitely still space to bring in a legit arm. But interesting to see how they will play with them - do you just rotate guys through the majors and AAA, or keep some of those guys as long arms in the pen?
I think this type of thing tends to work itself out. They have a fairly large group of guys, most of whom are probably AAAA type guys, some MLB RP, and maybe one or two that can hack it as MLB SP.
Let's say they start the season with two legit SP in the rotation (have to be free agents), Shoemaker, and then Waguespack and Zeuch as the #4 and #5. By the end of April, there's a good chance one of the top 3 will be injured and one of the bottom 2 will have been terrible for a month. Likely even worse. Cycle in the next two guys, maybe Pearson and Kay. Give them a month, and if they can't hack it, bring up the next group.
Also, of that list, I think most of them have already demonstrated they are not good enough or don't have good enough stuff to be handed a spot. If someone like Hatch or Murray are stellar in AAA next year, maybe they get a look. Guys like Thornton and Pannone have been given more than enough opportunity. Maybe they're bullpen pieces, but you could DFA them without losing any sleep. Same goes for almost half of the Jays 40-man roster, but that's another issue altogether.
I'm not under any illusion that Atkins is going to actually do this -- he'd rather waste another season sorting out which one or two of that pile of junk can actually play at the MLB level. He has spent four years acquiring extremely low upside "depth" so that they could do exactly what they did this year. They'll do the same next year and probably 2021 as well. Best case scenario, Atkins is gone after that. Their current approach has basically no prospect of success.