For sure, there would be a benefit in sticking with LoL: while having previous MOBA experience will certainly make the learning curve less steep, it won’t erase it completely.
AIs do respond to pings; however, the quality of their gameplay is variable, and depends on a number of factors, the difficulty setting being the most obvious: Veteran and Elite are the only levels that have a chance of putting up a somewhat decent fight, lower levels are mainly for those who are completely new to MOBAs, to lessen the initial impact.
Even then, you’ll notice differences based on the hero they’re playing, their team composition, as well as yours, the map and the specifics of the situation.
Training will become boring rather quickly, anyway, switch to VS AI Co-op instead, increasing the difficulty as you see fit. Up to a certain level, VS AI Elite remains useful to familiarize with a hero, with the idea of bringing it to Quick Match, and to warm up.
To experiment with a hero, there’s also a specific Try mode, which isn’t grouped with the others, and can be activated from the Collection screen.
Since the amount of experience awarded changes as the game gets longer, minion waves are worth more than hero kills, during the early game so, up to about level 10, players are often instructed to soak lanes.
In practice, you’ll often see both teams piling up on mid, in which case you should decide if joining your teammates isn’t the wiser option.
If soaking, the lane can be left as soon as it’s cleared, assuming there isn’t another reason for staying. Rotate and soak another, help team mates, then go back.
Pushing a lane alone is going to place your hero in an over-extended position, which can be exploited by the enemy, as you don’t have vision behind their towers or in the ‘jungle’.
So, and especially for split pushing, map awareness is a critical skill; if you don’t know where the enemy is, they could very well be coming for you, and you should act accordingly: remain close to your minions and towers, whenever in doubt.
Also pay attention to the enemy team’s composition: if they have ambushers, roamers, stealthed assassins, you should play under the assumption one’s always going to be around, looking for a chance to burst you down and/or deliver the finishing blow.
Finally, in draft-less modes, your team composition isn’t guaranteed to be suited to split pushing, or to support your hero properly.
Sylvanas has Haunting Wave that should be kept available as a way to quickly retreat, if the enemy shows up; Azmodan has a ton of HPs, and later a teleport talent IIRC.
Xul’s Bone Armor provides some shielding, but his health pool is more limited than Azmodan’s; whatever he has in the way of self-sustain is tied Cursed Strikes (IIRC), and puts him in an offensive, hence dangerous, position; he also has no escape, having to rely on map awareness and, preferably, the help of a support.
In practice, if there is no support, or the support doesn’t keep a close eye on me, I find myself having to hearth with some regularity, leading to increased downtime, in turn reducing Xul’s effectiveness significantly.
If retreating, remember you can use Spectral Scythe to deter pursuers; Bone Prison can also be exploited to create some distance. Both abilities, however, have a delay, so they have to be used pro-actively, otherwise your retreat could give them enough time for their ranged abilities or gap closers to become available again.