If you ask me as a devoted settler for the last 20 years, gems would be good but not great, coins again not great. Give us a granite deposit, add 2 or 3 more zones to our home zone, say 3 or 4 granite deposits, a few more marble, and a saltpeter or two.
Ive not been lvl50 for long but spending hours a day staring at the screen in the hope someone puts a reasonable trade in TO for granite so i can continue is rather tedious
Lvl49 and under have plenty to keep them occupied, new deposits and a few extra lvls will keep your regular players a lot happier.