ill create a small list, since i play both games:
-if you die, you lose gold in dota 2, which makes the game harder than lol because u get in a big gold/exp disadvantage since u have to spent money for a tp scroll to come back aswell.
- dota 2 hero mechanics are much harder to master, u cant just spam qwer and there are serveral heroes like invoker, chen, enchantress who have like 10 spells to use, not only 4. more to chen and enchantress below:
- micro management, in dota 2 there are heroes like chen and enchantress that can take jungle creeps under theier controll, all of them are freely moveable and have their own spells. u can controll up to 3 jungle creeps and need to tab/switch between all of them, navigate them in teamfights for good positioning or body blocks and use all of their spells, u will need all of them. so u basicly play 4 heroes at once which is a multi tasking job and extremly hard to master. lol doesnt even have this, sadly.
- the map is much darker in dota 2, u can time ganks better and hide in between trees, there is a river with 2 rune spots that spawn runes all 2 mins, u need to keep this spots warded and should have 1 player in your team that bottles the rune with a bottle item. also there is a day and night phase that accures heroes in a different way, some heroes have a great vision in night time, others have only a very small vision. this makes the game much harder than lol cause u have to time your ganks and teamfights on the current "day time" in dota.
- heroes like enigma, tidehunter etc. make teamfights way more exciting because they can turn around everything with their initiation, in lol the only one i know is sonas ult. and sona is a faceroll hero :S
- dota has an addictoinal role, the pusher. heroes like furion for example can kill trees and make treants out of them to be under his control and push down towers
- laning phase is way harder in dota, because u dont only last hit, you deny your own creeps aswell to get the enemy in a gold/exp disadvantage and outfarm him. this gives some epic battles about gold and exp graph, mostly on mid they play very well in this case. if one of ur lanes lack u need to gank, ganks happen way more often in dota because in lol its more about farm, in dota more about well timed ganks on day/night times, invisible runes etc.
- you can deny your own towers in dota 2, to not get the enemy get any gold from it. its hard to do but can turn around things and is very important
- the items are much harder to use in dota, u dont follow a standard build, all u buy depends on your enemies team and items, the majority of dota items have an active abillity so that means you always have to use a lot of keybinds for all your items, you need all of them in teamfights and need to time them very well. besides your spells of course :P in lol most items are passives only. also there are items like smoke bomb in dota which makes your whole team invisible in a small radius, you need to conter that with dust or sentry wards.
- as i said before, dota has day and night time, besides that it doesnt have a static field of view, you can abuse things like highgrounds (stairs) etc. to gain a bigger field of view than your enemy. also this makes placing wards harder than in lol, lol has always the same field of view. this makes dota way harder strategic and movement wise than lol.
my thoughts: lol is a nice and funny game for everyone, everyone can learn it doesnt matter how intelligent or unintelligent he is. boys or girls doesnt matter what age they are, everyone can have fun in lol because you learn it much faster, its reduced to the minimum tactics that dota had. so if u want some relaxing game and just fun, go to lol. if your are a tryhard player and enjoy competitive games and esport, you have the time and the EFFORT to learn the complex mechanics and want to master them go to dota. good plays are way more rewarding, it will be the hell at the beginning and you will be a noob for like half of the year, even if u nerdplay dota 2 every day. one little mistake will be unforgiven. u will get ganked hard and just be outplayed at the beginning until u know some tactics, by teams that just play tighter. but winning in dota feels much more deserved, you have some epic 1hour+ games and you have to focus and do SO many things and then u do some perfect plays and win a tight game, feels amazing.
maybe i forgot some parts but well, be free to add some :P