As long as you really shoot a good mix of grounds (I will have done 19 or 20 different ones by the end of this period - and they can't all be easy..) then following your average over the years is interesting and should actually spur you on to get better. But once again, it must be said that you are daft to kid yourself and seek out only high scoring shoots.
Classes is a different topic, although it does provide visible steps on the ladder. The system is so familiar to everybody now that you couldn't change it without an uprising. But, if you could wipe everybody's memory clean and start again tomorrow, I reckon it would make more sense to have no classes, but pay down to 15th place at a 150 entry shoot (for example). No birds only entries. Remember, nobody would consider it an option or miss it if it had never been offered. (And entry fees wouldn't be £5 more than BO is now, because everybody is chipping in) I reckon most people who have a bit of experience have a chance of being in the top 10% on a good day.
Tin Hat.