Is XP/Level the only advantage you get over the opponent since there are no items?
There's no need to farm or last hit(except the last hit passive heroes)?

You need xp/lvl as well as winning/controlling objectives.

With that being said though, sometimes you can win more xp/lvl by letting the other team get a certain objective. It is rare but it really just depends on what your team is doing while they are securing the objective for that map.


There are also camps that you can get for some xp but create a lot of lane pressure for your opponents to deal with. This game is much easier (mechanically speaking) than lol or dota but it also has a lot more strategy at higher levels of play.

There sometimes can be a need to farm, and be NEAR minions when they die (for reasons other than soaking experience from lanes)
For instance, after Nazeebo auto attacks or does ANY SPELL DAMAGE to a target, his poison remains for 4 seconds.. If the minion is killed within 4 seconds, you gain infinitely 5 health and 3 mana (assuming you took Death Ritual).

Other Heroes can spec Seasoned Marksman, where you have to be in a close range when a minion dies in order to receive one of six needed stacks for +1 Auto attack damage.
2 hero takedowns = +1 AD

You can also farm regeneration globes by roaming lanes and killing the center spell caster minion. This requires the Regeneration Master talent provided by several heroes.

Objectives are the main key to winning for most maps. To get the objectives it helps if you're higher level. Just a couple thoughts