The way I see it we already have one of the top disruptive DTs in the league in Jason Hatcher who seems to have come into his own the last couple of years. Even though he is 31 he actually hasn't played a lot of snaps of high level football so his body may not have absorbed as much punishment as is typical. I think he should be a good 3-tech for us next year.
As for the 5-tech LDE, I think Tyrone Crawford and Sean Lissemore can play that role fine.
Now for the 1-tech, this is where we struggle. Last year Brent played most of the snaps but no one knows his status for next year. Ratliff can play here but he is coming off an injury plagued year and we may not be able to rely upon him.
I think our biggest hole is 1-tech but I would just take the best player available since our 2 best interior players are in their 30s and Rat will be cut next year and Hatcher will be a FA. So either way we need interior players badly and I wouldn't mind if we traded down a bit and ended up with 2 DTs in the first two rounds with maybe an OG thrown in there as well.