I am having a lot of problems understanding where you are coming from with your statements. I have owned several expensive sticks and the X-45 is right up there with the best of them --and for a lot less money.
As for size --I am a grown man and have at least average size hands. I have no problem with the size of the stick --in fact I am about to make a base attachment so that I can rest my hand about 1/2 inch higher up the stick shaft. With my index finger on the trigger and my little finger on the "pinkie switch" I have about 1/4 inch travel with my other two fingers between the two switches --- that is plenty of room.
As for stifness. I can control the flight of my planes in MSFS, Falcon4 and LOMAC with ease. I can smoothly move the planes micro amounts with no effort.
However you do have to adjust the stick sensitivity in each sim to be able to do this --that is normal and expected.
I have heard of others using cable ties to loosen the stick spring a little but I have not found it to be necessary. My X-45 is smooth and light on the touch.
LOMAC needs serious sensitivity adjustments in the input menu for most all sticks. These adjustments will lessen the sensitivity from the default settings. This appears to be your problem with "overcontrolling" The overcontrolling can be dampened out and the stick made to behave by making changes to the sensitivity curves.
Start out by setting the sensitivity values as follows---
Pitch ------
Shift at 80
dead zone at 10
curv at 25
Roll --
settings same as for pitch
Rudder ---------
Shift at 100
dead zone at 0
Curv at 25
Make these adjustments and if you do not like them then make small changes until you find a set of conditions that you prefer better. But do not expect things to get better unless you make some adjustments.