On maps with lots of entrances, I like it when there are entrances which primarily have a certain type of enemy come out of them.
On eventide fortress, the east entrance is entirely runners, so you can plan on using traps which are great against them (brimstone, haymakers, ballistas etc)
On highlands (rift lord), the west entrance is elementals, middle is mostly heavy minions, and east is runners (for most waves). This means flip traps are great for west, a dense killbox is great for middle, and anti-runner traps are great for east.
I would like to see this done more on future maps.
I would also like to see entrances with just stilt orcs. These are cool in that they avoid floor traps, but right now they're mixed in with other minions on every entrance, so you really don't change strategy much.
Along this same line, I would like to suggest a new type of minion: Armored Kobolds.
The idea is that they would move slowly, have a ton of health (and/or damage reduction), but be very susceptible to physics traps and knockback abilities. This would add strategic variety as currently all minions with high health are also resistant to physics.