If you or a friend are new to Dota, the hero you should be playing is

Techies.
No, wait, don't leave yet, hear me out I'm being perfectly serious. Dota is a hard game, and its high barrier of entry has turned away many new players before they have had a real chance to love the game. It's important to look at the new player experience, and address the things that cause the biggest issues. What are these things? Well, they are

Lack of hero knowledge: New players just don't know what heroes do, and don't know how to react when a particular enemy hero is near them.
Dying alot: Dying is not fun because it forces a timeout on the player as well as a hit to the net worth. New players don't have the game knowledge to know when they are safe or at risk of dying, and will die alot.
Last hitting: New players can find it difficult to last hit, as not only are you competing against the game mechanics of the timing of your attack, but also competing against an opponent who is trying to deny you.
Falling Behind: A symptom of the first 3, but felt extra hard as new player games usually last longer then they should, so the new player is suffering from being behind for longer.
Unable to get kills/Make Plays: because the player is behind, the impact they have is minimal, and they don't get to feel the positive "hell yeah" moments of dota.
Don't watch minimap: New players, and even veterans, don't watch the minimap as much as they should.

So now we have a workable list of things that cause new players problems. Although its not complete, its serviceable. Now, I claimed that Techies is the hero you should play as a new player. Lets see how Techies addresses all of these points of trouble. The first thing is that, Techies doesn't interact with enemy heroes directly, he puts mines down, and the mines then interact with enemies. Because of this, Techies can stay far away from enemies, and doesn't really care what those can do. You don't care how much damage they can do, what kind of sick cc they have. You only care about getting their health bar to zero. So, in this sense, lacking the game knowledge of what heroes do is not as big of an issue for Techies as it is with every other hero in the game. Furthermore, because you do not directly interact with the enemy heroes, Techies will be far from danger and thus won't be dying to / feeding the enemy. Even if you do find yourself in trouble, Techis has Blast Off! for a pocket deny. Even your deaths can feel like a victory if you manage to deny yourself! Techies doesn't need to worry about timing his auto attack for last hits, because his mines will 1-shot the wave for him. Getting kills on techies is easy even for new players. The only thing you have to do is place alot of remote mine close together, and then blow them up when an enemy walks over them. This can give the new players those "ha ha, I got you" moments which normally they would be deprived of on other heroes. Because they are getting kills, dying less, and getting last hits, they won't be falling behind as bad as they would on other heroes. Finally, and this is less about how fun it is for the new player, and more about becoming more skilled at the game, playing Techies will train you to be constantly looking at the minimap, as you need to watch over your previous mine stacks that you have so lovingly built up.

Because Techies is such a unique and different hero, he is able to address the issues facing new players in an equally unique and different way, to let new players have fun while playing their first games of Dota.