The problem with aram are aram-only accounts and the rerolls.
If you get a not poke champ, you reroll it(or atleast ~90% of the players do so), which ends with pokesetups on both sides in ~80% of the games. If you play anythin besides a hard engage comb or a poke comb, you have problems as you will face a pokecomb, and with out the potential of outlaneing, splitpush or farming, if you can't keep up with the poke you need atleast malphite levels of hardengage to beat a pokecomb.
Back in the days befor rerolls, aram was way more random. You could have great games with udyr as your enemys probably had similar melees like voli on their team, and poke especially early on was reduced alot by not haveing any aditional manasustain and not enough gold to start with the likes of a tear.