Yeah, on Psn it's generally always better to wait - many games are dropping 30-50% within months and even weeks sometimes.
Eshop is a different story unfortunately; 'sales' is a dirty word and almost everything is rrp which is usually a good £10-20 more than physical. Occasionally someone like Amazon will sell a code for the same price as physical, but generally you're getting screwed.
Problem is that Nintendo titles are evergreen - something like Mario kart is still going to be selling to new customers a year or two down the line at full price; compared to your FIFA's and whatnot that are front loaded and worth about 50p halfway through the year.
Rockstar games are the same as Nintendo really so no point waiting - gtaV is still selling big numbers for £30-40 quid secondhand!
