Checking random July dates it appears that you have four options if you go with DL:

1) ATL -- on a domestic 757. Solid option though not worth backtracking from DFW
2) SLC -- on a 739ER, do not book this
3) MSP -- on a domestic 757. Solid option and definitely better than ATL.
4) SEA -- one a 738 and a double connection from DFW.

From the above if you are wanting to switch to DL for this year, I would take the MSP option. The 757 is the best plane option available (though no lie-flat if in F, just regular domestic F) and looks like two different options that work with a DFW - MSP flight. Backup would be ATL (though that's a long very long flight even in F) -- would avoid SLC (unless it's 50% cheaper I can't think of a world in which the 739ER is worth flying) and the double connection for SEA makes no sense, especially since the 738 isn't anything special.

I'm not a big AA fan but honestly unless the price is way cheaper to for DL, it doesn't make sense to go with DL over the direct flight.