And no, we shouldn't decide not to improve the team at WR because we need a MLB.
This.
The only exception is if acquiring a WR denies you the opportunity to improve at MLB, as it is a larger need. If no MLB is available then there is no reason to not improve the WR position if it is possible and for the right price.
Jackson is also a more logical long-term piece. Mayo, Collins, and Hightower are all productive and are under contract together until at least the end of 2015 and if Hightowers option is picked up they are together until the end of 2016.
Edelman and LaFell are the only productive locks at WR for the foreseeable future. At the rate Dobson is going he may be looking for work at seasons end, Tyms has one catch, though his sample size is very small and he is basically a rookie to this system. Amendola has shown he can be productive, but a more productive teammate on a smaller contract apparently dislikes him and will do anything to wipe out any contributions he can make, basically a 6m/year decoy right now.
So we have 3 LB's locked up for at least the next 2, and potentially 3 seasons, all 3 are productive.
We have 2 WR's locked up for the next 2 seasons together.
BB is about helping the team right now when it comes to trades, but for those asking for a player like Lavonte David, I just can't see it happening, I can't see him cutting Mayo next season, you could say that he might be BB's favorite player, the other players call him BB's son.
Jackson, or another WR, makes a whole lot more sense from BB's long-term building philosophy.
..I also don't mind another 6'5" guy, can never have enough of those "catch radius" type guys, especially one who is averaging something like 17 yards per catch over his 9+ year career.