Technically--there was nothing wrong with Trinity. It provided all the basics that (IIRC) management here liked--including very strategic choke points at all 3 borders.
To "fix" Trinity--the main complaint used to be 2-fold....1) The monster high mountains on all three starting fronts, and 2) That it took a "long time" for any side to gain a clear or winning advantage to go to the next map.
Just take the mountains down to about 7 to 10K and reduce the base count amount by (+/-) 25%m on all three sides.
Leave the front bases alone and subtract from the extreme rear eschelon bases and then simply replace the HQ and strat locations by an equal but shorter distance but still have the option to have strats move further to the rear as before...only with fewer bases.
With fewer bases to take the map and mountains less than a 1/3rd of what they were before, most of the complaints that got Trinity tossed would be addressed.
You will still have a map that is good for GV battles, furballs, cv strategy, but yet is still large enough for those want to meet a foe out of the way for a in-game duel.