My gym

[Sassybynature]

Ok, so I need to rant. I have been using the same local Nuffield gym for around 10 years and i have made several friends from it. Used to love the classes and instructors but things have changed. I have enjoyed my time there, however, it has now really gone downhill,not sure my reasons are quite fair and don't like the way I am thinking. For example, last night there was a new instructor, he was overweight and just slobby looking. Doesn't really inspire me. This week I have to two Pump classes, one instructor felt it's her right to pick people out in front of the class and criticise. She comes across so bad, everyone talks badly of her. The other instructor was an older lady, late 50s, teaching who would just not shut up about just rubbish. Again, not very inspiring. Apparently, the good instructors are all leaving because Nuffield are only paying £20 for a class.
Now, I know I should just leave, but I used to love that gym. Would it be wrong to air my views to the manager?Are my reasons for disliking these instructors very shallow? The next nearest gym is a David Lloyd but it costs twice as much. How can I word it without coming across mean, I don't want the instructors to know, I won't be very welcomed any longer.