UKH

pondering if i should transfer from square taper to hollowtech when i replace the triple chainset on my touring bike. my main gripes with square taper is the flexing, creaking and bolts loosening. will hollowtech be better?

If you mean hollowtech 2, my issue has always been durability. I've had a good number of XT, Tiagra and ultegra level BBs seize up and fail. The opposite of experience with square taper which are usually very well sealed and last ages.

So if you abuse your bike the square taper makes sense but the hitch could be that there aren't many good quality square taper cranks on the market as they are now only fitted to lower spec bikes.

Hope are much better. Not square taper longevity but way, way better than even the expensive Shimano ones. 

Spa Cycles have a good range of square taper triples and rings to suit any desired gearing range.

But they do cost 4X as much. Swings and roundabouts I guess.

Touring bikes are by nature generally heavy and flexy. I've tried a few things on mine and ended up sticking with a square taper, an advantage being that I get to keep using my lovely Middleburn triple chainset. Unless I'm carrying a really heavy load, which I tend not to anymore, I also get away with a much more closely-spaced cassette than I would otherwise. 

But they easily last more than 4x longer.

There's something wrong with your square taper chainset or the way it is installed. I've had the same square taper chainset on my touring bike since 1986 and it's never flexed, creaked or had a bolt come loose. Still runs on its same TA bottom bracket, but I did treat it to a new set of loose ball bearings at one point.

Some people say it's important to only fit JIS tapered chainsets on JIS tapered bottom brackets, and visa-versa on ISO, but I've run Campag chainsets on Shinmano bottom brackets for decades with no issues.

Did you fit your square taper cranks with the manufacturer specified torque?

Previously run Shimano SLX BB's on the mountain bike and found that even with that quality, water ingress can spanner bearings pretty quickly without careful maintenance.  That was riding through winter slop, though....  On the upside, the Hollowtech 2 system has a very good crank/axle interface and is very simple to fit and work with compared to "traditional" square taper BB's.

FWIW... Just got a 1980 Holdsworth Mistral (classic Reynolds 531DB touring frameset) back on the road and fitted the Sun XCD crankset.  It's 50.4mm BCD so takes TA chainrings, giving lots of flexibility for ratios, as well as looking similar to the classic TA chainset so suits the bike.  Double ring at front and running 34T small to 32T rear.  Massive jumps in ratios on a six sprocket freewheel for that full retro experience!  Cheating by running a modern, sealed Shimano UN-55 BB which are reasonably priced and ubiquitous.  (The Mistral is superb ride for a factory build.)