Interesting...I also just got a Stretch sprint and the lock bar tension is typical (medium)...sounds like you might have a bad one?My Stretch 2 V-Toku2 arrived today.
Very comfortable handle design,,, excellent QC, fit and finish great, well centered blade, factory sharp edge overall well done.
I find very little difference with in hand comfort between Stretch 1 & 2 models.
I do prefer the blade shape on Stretch 1.
One noticeable problem with the new knife is the tension spring on the lockbar,,, it takes 2x-3x the amount of force/pressure to disengage and release compared to my 3 other Stretch 1 knives. Very annoying when required to use excessive thumb pressure. The lockbar appears to be identical to the Endura 4 and tomorrow I will use an older Endura 4 with easier opening and swap out the leaf springs.
Now SMKW is showing them out of stock and I still have no notification of shipping....SMKW (who I preordered this from, again, on 1/4/18) is also now showing them in stock but I've received no notification of shipping for my pre-order as of yet.
I really hope there is not a backspring issue across the board with this Sprint...
IMO I don't see the big deal with a strong spring on the lock bar.
How did you modify the Delica 4 lock spring?