Flyaways
There are three components to any aircraft simulator:
1 The mathematical model of the subject aircraft aerodynamics, propulsion and equations of motion etc.
2. The outside world display.
3 The motion system.
If you pour enough money into 1 and 2 they can theoretically be perfect.
No matter how much money you spend on 3 it can only ever be a very rough representation of aspects of the real motion. Indeed it always has elements of false cues (cues that are not in the aircraft in flight).
When assessing (or developing) a simulation I always do it motion off. This way you know what you are dealing with and that the end result will always be harder to fly than the real thing because you are missing the real motion cues. In flight motion cues felt through the seat of the pants give you just that little advance warning of what is happening before you see it on the aircraft instrument displays or the outside world display. That is the little bit of help you are missing in a fixed base sim.
As to whether will you ever forget you are in a sim and not an aeroplane is a very interesting matter.
In my experience pilots fall into two categories - those that given enough workload and need to concentrate to try and achieve the task will certainly forget they are in a sim. (I am one of those) and those that never forget it is a sim. whatever the circumstances. I suspect the latter are probably in a minority but I do not know that to be a fact.
Bottom line so far as you are concerned forget any lack of motion - it is not an issue.
BTW you should NEVER control an aircraft primarily based on the seat of your pants but on the outside world picture and the instruments because in many circrcumstances our inner ears can get completly screwed up by flying so they MUST be ignored. (They were after all developed to help us move about on our hind legs or perhaps horses)