Agreed. Unless some great prospect (not following College ball by the way, so no idea at all) at DE falls to the Pats I don't see a big need to draft a DE early. Right now the DEs under contract for next year are Trey Flowers (4th year by then), Deatrich Wise (2nd year), Derek Rivers (2nd year). That's plenty young. Good would be signing a veteran who still has got a few years left in the tank and isn't too expensive (Ziggy Ansah? Demarcus Lawrence is perhaps the top FA DE out there, but he is going to fetch a nice contract).
T. Flowers and Wise are probably a good base. Lee, with a full season of "indoctrination" could be a valuable rotational piece. Guy often plays a "heavy end" role in mixed fronts, as does A. Butler.
Hightower has done well in an OLB/DE role. Rivers, at around 250 lbs, might be good there, too. The Pats also have Keionta Davis (6030/271) on NFI, and Langi.
McClellin may or may not be back (he's under contract thru 2018).
As far as adding a FA vet, I'd be thinking older and cheaper - more a journeyman type. An
extreme example might be William Hayes, age 32 and recently put on IR for a hammy.
The 'Fins traded a 6th to the Rams last season for Hayes and his $4.75M contract and he ended up being a little-used back up to rookie Charles Harris. Hayes was a reliable 45-tackles/5-sacks per year guy for the Rams for five seasons before they traded him. A guy like that might be worth the vet minimum to the Pats to have on the 90-man roster through Camp.
Anyway, there are a couple-three similar guys who are UFA in 2018, and there will likely be a couple-three others on the street from cap-cuts in Feb/March.