I had virtually the same experience with my 6'9" M-XF Elite Tech SM spinning... My son broke it during a cast this past summer, so I sent it in under warranty. I knew that Fenwick had discontinued the ET Smallmouth, so I figured they'd probably give me something different. Sure enough, a couple of weeks later an Elite Tech Bass ETB69M-MFS - 6'9" medium fast one piece.
My feelings were the same a yours regarding the replacement rod. The extra fast ETS was really a special rod with nice fast crisp action. The ETB is average at best, unlike the SM which was exceptional. I didn't bother dealing with trading the ET Bass back for another model, perhaps I should have. Possibly the ETB610ML-XFS (6'10" medium-light extra-fast)would have been more like the old rod.
It's interesting that others feel the same as me regarding the replacement rods. At first I thought it was all in my head.Not that it matters to the fish... but, I also liked the color of the ET Smallmouth, I had it paired with a dark green Shimano Symetre. They looked great together. The green Symetre on the brown ET Bass doesn't look quite right. I wish I could get the old ET SM rod back again.