I actually prefer my pocket clips to be more on the looser side.
Almost all of my knives I 5th pocket carry, so they stay in no matter what the case.
But for deployment, having a looser clip means the quicker I am.
Now for my larger knives that I do clip into my front right pocket, I like them to be slightly tighter but not by much.
For example my Strider SnG DGG is very tight and mixed with the Gunner Grips that's why their nicknamed pocket shredders.
But another example, on my TSF Beast, its a very light clip and I can extract and deploy the blade lightning fast.
Plus the blade rolls on IKBS bearings and is tuned to open with the lightest thumb flick possible.
All in all its totally up to the user and how he or she carries their knives.