Why not both?
Bortles likely signs a short term deal 1/2 year deal. Gordon (or any 5th-7th round drafted QB) could end up on PS
I feel like in today's NFL the best use of a QB2 spot is development.
On one hand you have Warner with the Rams or the Eagles winning it all with Foles. But on the other side of that "what happens if your backup QB has to take over" ledger there's a ton of ugly result. So overall if you lose your QB1 you're usually going to be up shit creek.
So now enter the value of starting QB pay. It is going to be harder for teams to tie up another $5M+ for a good backup when they're already putting out $30M+ for a starting signal caller. This will force teams to consider cheaper alternatives, i.e. draftees, and they will realize that having a QB developing on the roster in today's NFL might be more valuable than the extra wins you'd get from a veteran backup.
Now granted you could simply have a QB3 on your roster and eat your cake too. But is that wise to use a roster spot for that? I mean case by case and all that obviously. Still, I would prefer another young skill position or lineman.
Thus while some will tell me I am crazy I believe the future of QB2 is going to be cheap, developing labor.