HARRY - Atleast HALF of those problems you claim the manual trans/clutches have I have NEVER experienced in FIFTY years of running GD CC's, and the other half have remedies.
Yes, T/O bearing fail, and if you really want to make them fail quick, put a much stiffer pressure sping than needed in the clutch, that kills them quick! Or ride the clutch pedal, or let the return spring get bad like Don T's, and you'll kill the T/O bearing too. But with stock parts and an operator that's read the manual about proper operation of the clutch, 40-50 yr life should be doable. Teaser spings live at 100% coil bind when the clutch is engaged, only extends when you push the clutch in, ANY spring will break when repeatedly placed in coil bind. You just replace them every time you have a clutch apart. When they break, they don't "rattle", because the pressure sping has compressed them into coil bind, A broken teaser spring makes it hard to ease the clutch out gently, but you can run a GD CC forever with a broken teaser spring and not know it except for the grabby engagement.
I've never had a CC clutch friction disk excplode, but if abused bad enough, or dropped & cracked when out of the tractor, I guess it could happen. Best change IH made to the clutch disk was bonding two thinner pieces of friction material to a thin piece of sheet metal. The disk has a V-E-R-Y long life even if abused or slipped a lot. The one in my 72 is 32 yrs old and no signs of giving up yet.
Never had a pressure spring break, the factory spring in my 72 did compress and lost a bit of clamping pressure. Typical of compression coil springs, or Springs in general. You can shim them, or use the movable clamping collar on the driveshaft instead of the roll pin * washer like IH used, restores the sagged spring to OEM pressures. BT-DT.
The ONLY roll pin hole that wears on the driveshaft is the very rear-most hole, and ONLY on 10 HP & greater tractors, the frt hole on the coupler right in frt of the reduction housing. I've broken a roll pin twice and replaced a drive shaft TWICE because of that hole in the DS wallowing out. The 1018 CRS IH used was NOT the right steel for that application, I was going to make a new DS from "Stress-Proof" steel (look it up!) but used a 4140 prehard MWSC DS instead. I'll let you know how that works in 20 more YEARS, which is the minimum life expectancy of the OEM DS in HARD use. That hole is the ONLY place in the whole drive line where ONE 1/4" dia. roll pin drives the whole tractor, well, the back hole on the coupler does too, but the input shaft of the reduction housing is 1040/1045 carburized steel, MUCH stronger/harder. IH should have made the coupler longer and put TWO 1/4" dia roll pins in the couple/drivesahft. I was going to do that on my 72, but got the MWSC clutch instead. If it fails in less than 20 years I will make my next driveshaft, I still have the 5/8" dia. Stress-Proof steel bar. MTD on the post-IH GD's used a shock absorbing coupler similar in design to a LoveJoy coupling. Problem solved!
The anti-rattle springs WILL fly out if installed "By the manual", because the manual is WRONG, put the spring or Springs on the drive plate's roll pins THEN slide the engine back and trap the springs between the backing plate & clutch disk. The 3 anti-rattle spings have stayed put for well over 30 yrs since I installed them that way. And frankly, even without the springs, the rattle is barely audible. My PTO clutches rattle MUCH more whether engaged or disengaged. and even when I had a muffler I could barely hear the PTO clutch.
So yes, if you like to repair CC's, GET A HYDRO! Change the Hy-Tran & filter every 100-150 hrs with two gallons of $15/gal Hy-Tran, repair the trunnion, replace the Cork Gasket, and rear axle seals, and rag joints. My 982 is 33 yrs old, the trunnion was badly worn and poorly repaired when I bought it 13 yrs ago @ 20 yrs of age so I fixed it better than OEM when the prior reapir failed and I almost drove into the concrete wall on the back of my shop 10 yrs ago. Tractor wouldn't stop, and only moving the speed control lever into full reverse slowed it down. The cork gasket has leaked since the first night I parked it in the shop. It stops leaking once it's about a half quart low, so if your Hydro doesn't leak, you need to add some Hy-Tran.
It's not that I'm "Anti-Hydro", but just realistic, the hydro & GD Cc's have things that wear and deteriorate, neither one are "Perfect" but both are pretty darned good compared to the competition. But saying the GD's with their dry disk clutch have to be replaced every 10-20 yrs is just WRONG. I have 59 & 62 yr old FARMALL full size tractors out in the shop that were worked HARD, and both still have the factory clutches in them. And both are used on loaders, which anybody whode run loaders know you use the clutch A LOT. The M has been a loader tractor it's entire life, 62 yrs! 45-50 yr old CC's should/could last this long too.