Disclaimer: bottom right few heroes were NOT in the calculated version by DotaMetrics, therefor I did not include them. If/when DotaMetrics recalculates these farm dependency heroes I will redo the layout.
Full credit of research goes to: http://dotametrics.wordpress.com/2013/01/21/the-dota-2-metagame/
In Who is the Most Farm Dependent Hero?, I attempted to measure CS scaling. While there are some issues primarily rising from the small sample size, shifts in how Normal/High/Very High play the game, and emerging trends during 6.74 (Bounty Hunter is likely too high, for example, and Tiny is likely too low) I’m generally pretty happy with how it turned out.
The heroes new players should focus on learning first are at the top. Learning heroes in this order can improve the player's skills very fast as they tend to learn the most balanced heroes first. Work your way on down until you've learned them all.
Centre line mid: Most fun heroes
Centre line top: Fun Fat heroes
Centre line bot: Fun supports
Left group top: Fun gankers/roamers
Left group bot: Fun crowd control
Right group: Fun midders
Far Right: Boring farmers
Far Left: Heroes I dont play much, but should try