Kaoticmagic's wall of text has some good points but I have some critiques and comments.
Saying mix of single-target and AoE doesn't synergize is stupid. Yeah, your team works awesome if you all are super single-target and focus fire through your kill order. Yeah, your team works awesome if you all hit your combos and the enemy team drops in unison. However, to say that your team won't work because one person's ult is AoE and one person's ult is single-target is a little blind. Team compositions are completely variable and you may find the need to use AoE to disrupt your opponents in a fight to make space for your single-target champions to focus their targets without getting destroyed themselves.
Everyone agrees on one thing thought. The ability to go over/through walls is a huge advantage in the treeline. Walls are notoriously thin and make transition time between jungle-lane or lane-lane extremely fast making normal MIA calls ineffective and gives some champions insane escape.
We can all agree jungle/ganking is important given the proximity of the smaller map.
Cannot stress the map control part regarding wards. Wards last 3 minutes just like in SR but given the size of the map and average duration of games (mine all end at 15 minutes for some reason), you usually get more mileage out of them. Map awareness is essential since many champions can transition lanes in mere seconds. Also, warding bushes around dragon (especially the circular bush near the enemy's top outer tower) allows you to kill dragon safely or be aware of the impending team fight. Finally, as you begin to push towers and into base, you may want to have nearby bushes warded (the Y shaped bushes or the middle oval bushes) since attacks can swiftly emerge from these locations and catch your team out of position and overextended.
I got some more, but I can't be giving all my tricks away. Especially in a generic thread like this.