Hello! I play dota since dota 1, work as gamedesigner in small company and sometime try to analys big game. So i just started to play tutorial missions and i have a several things and ideas for you. I hope this information will be useful for devs.

1. Tutoriar UI don't help with quest goals. For example, then player asked to open shop, "shop" button don't marks by any effetc. New players in dota may spend a lot of time to find it. And you don't tell to player what he can also use hot key for shop. Same with navigating on map. Yes, you make marks on minimap but i think what if you attach some "ping" effects and sound like in game it will be more useful.
2. Last Hits as the most hard thing for beginning. Before reborn you had good tutorial for LH with full information about it: why you need to LH enemies creeps and denie your, how to do it and how much hp need to LH or denie. In new tutorial you said only what creeps give exp (but it didn't reque LH lol) and bounty and what hp of target need to be "low" (how much low? less of 50% or what?). Also since reborn you remowed marks,wich help to LH, why?
Also i think what if you will give to player a quest for 5 or 10 LH it will be better to understand important of these action.
3. A the beginning you show to player items in shop and force player to buy items for stats. But you didn't said why he need these items, what stats is and what they give. With items for regen another problem: you didn't said what at once time only 1 same item available to use (for example: only 1 tango works and no need to eat 2 or more).
4. Aggro of creeps and towers. You show it but didn't said what is it. Why cpeeps had "!" above their heads, why tower hit you, how it work, how to protect yourself. Also final quest is about to destroy tower but you didn't said why is so important to destroy towers, what they give to player and what player can denied tower.

And why you remored advices from loading screens? They still showing if you watch games but then you play it' didn't. I don't know why you did it but i know a lot of people who like it and really miss it. Btw you need to work on form of these advices because now many of them have a blurred or double meaning.
And why you removed tutorial map, archonicus (i don't really remember name of the book with plot of dota 2) and sniper hats? It was so cool and motivate players for receive tutorial. You can also make a trophy for the 100% passage of tutorial.

I hope it was useful information for devs and sorry for my bad english.
Topic will be updated if i will find something new.