as bad as lol is dota is worse but in different ways. Primarily some of its worst problems are:
vision: towers give no true sight and theres no where safe on the map against fast people or invisible people so supports in that game are truely ward bots moreso than anytime in the history of LoL
on the subject of supports: supps in dota are not much like in lol, even from the old days when they were less battle focused than they are now. Supports in dota spend almost all of their gold on vision items and buying a courier (couriers fly items to people because going back to base is not as free or common in dota) to the point that they usually end up buying maybe one midrange item and have nothing else except boots and wards unless their team gets ahead and they happen to have gold to spare but that is by no means common or the intention. Supports also have to micromanage spawns nearby which some people like but most people who come from lol find it to be tedious and boring. All of this translates to supports being free kills (aka free money) for the enemy team and of little use aside from warding by midgame due to lack of items to stay relevant. Imagine soraka with 300g boots, a cheap ap item, some potions, and some wards and thats basically a support in dota.
turning: heroes have turning speed which basically boils down to being ministunned if youre trying to attack something behind you like for instance when youre running away so in many cases trying to use an ability to defend yourself will simply effect a ministun and at best waste any time you bought yourself using a cc skill due to distance lost while turning and turning back
high ground: there are elevation changes at various points on the map and players with low ground miss most of their attacks, seems strategic at first but ends up just being an obstacle to fun
excessive range on ranged champs: you know how janna can tornado ppl from off screen? imagine that range but now imagine if vayne had it on her basic attacks, thats what you deal with with mutliple heroes due to how large the range gap is between ranged and melee champs
hard cc: hard cc is far more able to be chained and also tends to be longer in dota than in lol so stun locking is something you have to be aware of and can easily ruin you, there is a very expensive item that can counter it but due to its cost and the economy of the game it is not wise for most heros to buy it
reliance on items: items in dota tend to provide far more in the way of abilities and so this translates to gold acquisition being far more integral to winning than in lol, plus when you die you lose some gold which makes it all the worse
no ff: probably one of the worst things youll experience when youre new to the game especially is the lack of forfeit. like oh you have some afk on your team and are losing horribly and want to ff? nope. you have to sit there and suffer, if the enemy team is nice they end it quickly, if theyre not they can trap you in the fountain and spawn kill you over and over and over for as long as they want or until you quit and recieve a penalty. That can also happen if they just get ahead and since you lose gold when you die that means that theres no way for you to catch up, easily bad enough to recommend against trying dota.