Quite honestly, if you are put off by the graphics maybe this isn't a game for you, but you can use shaders and packs as it was explained to make it look beautiful. I actually prefer it to run smoothly and don't care about the graphics much.
It is very easy to learn, at least the basic mechanics of it all and the most common crafting recepies. Then the content is so immense that you could spend years learning it all, I mean, people create freaking working computers inside the game using redstone circuits. Maybe you are into farming, or exploring, setting down, building a nice house and mining or learning spells or how to brew potions. That type of stuff.
The game has no clear progression but if you are asking how long it takes to "beat it", well, the answer is: a lot! there is no way for you to speed run this, reaching The End takes time, even reaching The Nether takes time, even if you manage to find diamonds quickly, mine obsidian and enter the portal you still have to prepare yourself in terms of the quality of your armor and weapon to survive in there.
You can ditch all that survival stuff and just play online something like sky wars, that's a lot of fun.