Yeah, they need another pitcher to make everyone feel more confident in that staff, I get that, but why trade away 2 of your best young players to do that? Ultimately, it depends on who they get. If they can get Hellickson? They should pull the trigger, but who else is out there that would give the Angels value?
Personally, I like the idea of trading Wells for a pitcher with a bloated contract, on a team that needs OF depth and then eating the difference in the salary. Someone like Lackey or Zito. That would be the ultimate Win/Win. It would allow Borjous to get more PT as the undisputed 4th OF'er and you keep Trumbo's intimidation factor in the middle of your line-up, plus you get rid of the King of pop-up and add a decent starter to fill out the rotation.
Or how about Porcello for Conger, Cron, and/or Maronde? I think something like that could work, then they get a solid young ground ball pitcher, who would benefit greatly from getting away from the Tigers infield "defense".
Or how about don't make a trade at all? There are plenty of solid options still out on the market. Jackson is a possibility. You also have solid options like Saunders, Liriano, Loshe, and Marcum, none of them will break the bank. You might even be able to get a guy on Loshe on a 1 year deal once he realizes no one will pay him what he thinks he's worth. You also have real bargain buys like Derek Lowe and Dallas Braden, both of them are more than capable as #4/5 starters.
Basically, there's no reason to sacrifice guys like Borjous or Trumbo for a #3/4/5 starter, mainly because there are still plenty of cheap, solid options currently on the market, and other trade chips at their disposal.
You also have to take the long view of things, and by long view, I mean next year. Kendrys Morales will be a FA at the end of the year, and he's a Boras client. There's a very good chance he will be gone, especially if he regains his pre-injury form. Then you could have Trumbo DH and Borjous start in the outfield, unless you have complete faith in Calhoun.
There's just so many possibilities, and potential fits, that they shouldn't panic and trade a GG center fielder or a 30+ HR lock for a quick fix this year. If they can get a GREAT pitcher, then yes, do it, anything else, WHY?