I really would like to have proper pitstops. It is a bit silly to be able to go full speed into the pitlane, get right into the pit cut scene, and then spit out the pit exit. A tire stop at most tracks only costs maybe 7-10 seconds (with a couple of exceptions).
It should be like in most other sims, that you need to slow down before pit-entry, and then drive at appropriate speed until your box, where you have your stop. Then drive out under pit limit. Of course it should be adjustable so you can have the pit sequence automated, or fully manual. Extra bonus would be to have the option of adjusting the fuel refill rate and the speed of tire change to reflect real life. For example, a GT3 pitstop takes much longer time then F1.
With the current super quick pitstops it makes it harder to set up the race for different tire strategies, as the softer compounds + more stops always seems to come out on top.
Just my 2 cents, but somehow I'm expecting similar pit procedure as in GT Sport.