My first question has to be:  What are you going to do with the car?  Is it a stockish highway cruiser, an occasional drag car, what?  What do you hope to achieve by modifying the transmission? 
When I built the AOD for the Heap a number of people suggested that i should install a "shift Kit", hardened OD input shaft, different valve body, on and on.  In the end after some research I put in good frictions and steels, a top of the line OD band, and added a couple of frictions and steels to the (I think) direct clutch pack.  I don't race it I just drive it so I just wanted it to operate well and last a while.  40K so far and it seems to be fine.  I did essentially the same thing to the 4R70W that is waiting for me to find a winter with nothing else going on so I can install it.
If you are leaning toward a transmission upgrade I think I'd just save my $$ and put it toward the AOD or better yet, the 4R70W.  JMO.
Oh, I believe the shift kit can be installed without pulling the trans.  Usually it involves pulling the valve body and making some modifications there.  That can be done by dropping the pan.

BB1
 

Excellent advice.

6sally6 wrote:

I'm a BIG fan of shift 'improving'kits.
"They-say"...by improving the shirt between gears it lowers the slippage between gears. Smoothness=slippage.. which = wear.
I installed my first kit (B&M) in a 70 Dodge Challenger= a looong time ago. It was my main transportation = the wife drove it.
Part throttle with a 383/335HP engine would give a 'firm' butt-knot harsh shift. Anything more than part throttle would make those L-60-14's (remember those?!) really bark!
In drive it would shift through all 3 gears as before.
Fast forward to my 91 S-10 with the 4.3 engine. TransGO kit supplied everything for improved shifts. Same results as the Old Challenger !
I also use B&M TrickShift trans fluid in both vehicles.
I've done a 'little' research and I believe the Trick Shift is basically the old Ford Type-F fluid.
NEVER had any issues caused by installing the kit.
It's one of those things where............you ask yourself, "why did I not do this years age"!
IF....I was a little younger and maybe a little braver I would tear into the governor section of my little S-10 and maybe modify it to go a little longer between shifts from first to second. I believe GM designed it to shift into high gear faster to help with fuel mileage.
Ya gotta change out the fluid anyway.......why not install a shift kit while the fluid is out?!!!
6sally6

Yep.  The guys at the trans shop used to refer to F type as the "poor man's shift kit".

Your S10 probably had a 700R4.  I've rebuilt them, pretty simple really.  You can calibrate the shift points by messing with the governor, but stock almost all of them would not shift 4th at full throttle, or hold fourth at anything other than light throttle.  There are some parts from the Corvette and the aftermarket that make both of those problems disappear.  If you ever get into one again talk to Dana at Pro Built.  He helped design a lot of the parts he recommends and sells.  I used one of his kits in my Blazer and it was awesome.  Snap your neck at full throttle, smoother than stock at part throttle without a bunch of slip.  He actually gives you instructions on how to make a few tweaks to the TransGo shift kit.  It really works.  He has one in a Camaro that runs 9s.  Last we spoke it had made thousands of passes without a single tranny issue. 
 

Excellent inputs. I think I'll do the shift kit. Relatively inexpensive and I can always go back. Thanks for the response!