I’m looking at some used gear tomorrow, getting a left hand baitcaster setup to try.  One of the rods is a available is a Fenwick EliteTech 7’ medium, which I believe is a fast action.  What niche might that rod fill?

The discontinued Smallmouth version of that rod was my favorite for years.  Snapped it on a large cat this summer.   Was my Rage Rig and skipping rod.

They have nice actions and are well balanced, well made rods.

That would be a great rod for Texas rigged tubes, among other things. It's a very versatile rod that could be the rod you use for a bunch of different lures. Only trial and error will tell you for sure, but either way, it's a rod that is worth owning.

lightly-weighted Plastics in open-water or light-cover situations -- light t-rigged worms, flukes, tubes, grubs, paddle-tailed swimbaits. Also underspins, finesse jigs, smaller (3/16-1/4oz or thereabouts) spinnerbaits and buzzbaits...

 

Probably more a jack-of-all-trades rod than a niche rod -- it should be very competent at many applications (other than heavy-cover) as long as you stay within it's lure-weight rating.