Yeah it doesn’t take much effort to move the slide. Would it make sense to swap to a full length guide rod with a new recoil spring?
A new recoil spring is cheap enough, I'd say just order one and try it, see if it fixes it...
Let me add, with my hand built 80% frame 1911, that cut the rails for a particularly tight slide with very little clearance, I found over lubing the rails, even with oil for the low temps I was using it, caused the slide to drag and short stroke... ...this slide is much tighter than any other production slide I have seen, and I have concluded to tight, if I use to much oil and the weather is cool enough to thicken it a little or some carbon mixes in the oil and thickens it even in warm weather, my slide will short stroke.... ....so look at that also, if you have a slide so tight that it has no perceptible play when heavily lubed, that might be the same problem as mine... BTW, wiping my rails down to just barely a film left on the rails, it works flawlessly on that tight slide...
I have absolutely no experience with alternate recoil spring systems in the 1911....
Other than trying the Colt Dual Spring system (its pretty much the same as the old system, just a little narrower guide rod to fit the inner spring that goes inside the outer spring....
Or the Wilson Combat Flat Spring recoil spring, which also requires a narrower guide rod....
The manufacturers will only claim the dual spring and flat spring will last much longer than the conventional coil spring... ...some say it reduces felt recoil slightly.... ....others say it doesn't... ...I "think" I feel a little less recoil, but without a way to actual measure, I totally admit I am likely feeling what I want to believe I'm feeling and there is likely no difference...
The downside of the narrower guide rod for the dual spring or flat spring; during re-assembly, inserting the spring and trying to get it on the guide rod is near impossible, being narrower it always falls off axis and won't line up with the spring....
...But its easy to adapt, just install the bushing on the barrel and spring on the guide rod before you re-install the slide on the frame, and it goes together just as fast and just easy...
Wilson Combat sells the flat spring with the guide rod as a kit, for like $20, the colt dual spring I got off brownell's and its always out of stock as well as the guide rod that has to be purchased separately, I had to back order them and wait months.. ...at the same time the wilson combat guide rod is the same dimensions as the colt, i.e. you can substitute it with the Colt Dual Spring... ...so if you're so inclined, these options are only a few bucks more, and still plenty cheap, at the worst, you get a spring that last many times longer than the conventional spring....