I have not run into any problems where the PCs are taking too many short rests. There is almost always some sort of time/rp pressure moving them forward. In 4e, my players quickly learned to burn encounter powers early in a fight because they knew those would recharge 90% of the time before the next encounter. In 5e, the dynamic is a bit different...they don't know for certain that a short rest will be a viable option and powers like Second Wind, Channel Divinity, Ki points and spell slots for (edit) Warlocks are something they don't want to waste on easy and medium encounters...they seem like they would rather just burn a few HP by letting a fight drag out an extra round. The only player I have that is quick to burn a resource is our wizard...last game, they ran into a wight and 5 shadows and quickly realized they were resistant to non-magical attacks...Fireball...encounter over. Then the wizard announced he's taking a short rest. This was mid dungeon with a 25% chance per 10 minutes for a random encounter. 6 wandering monster rolls later (nothing showed up) and they moved on...
This could have gone very badly for the party. I'm the sort of DM that runs a dynamic dungeon (like the kind suggested in the dungeon brawl thread). Many of the wandering monsters are the sort that will alert the rest of the dungeon to intruders...so a consequence of a short rest in the wrong place/time could make their lives a lot harder.
Typically my game has had 1 or 2 short rests per long rest and 6-8 encounters, but in my game encounters tend to get smudged together because my monsters react to the sounds of combat. The louder, the more likely...our warlock has shatter and likes to use it...
If your ratio of encounters to rests is low (2:1 or less) you want to stay away from easy and medium encounters as they just feel like time wasters. If it's very low you need to tend toward deadly encounters. If it is higher (3:1 or higher), medium and easy encounters become more useful.