Theres an upwards trend of games having low skill floor or what I prefer to refer to as a lower cost of entry in terms of skill. It makes them more accessible to the public, and less likely to give up in the early stages.

Also over complicated games make it tougher for viewership - which is a HUGE part of eSports now. Viewership is directly related to revenue (note: not the only relation) - as such simpler games to follow (For example, not needing to be able to see missed L-Cancels) can result in higher viewers. I HATE playing League of Legends (or any MOBA's) but actually enjoy watching it, because despite my lack of ability to play it - its enjoyable to watch and production value (and money to do so) is very good.

On the flip side I am not saying that Melee or any smash is unwatchable - I am actually referring to games that have previously been eSports games or wanted to be - WoW was dropped from MLG for just being to viewer unfriendly (the average top end wow player will have around 70 binds/buttons. Guild Wars 2, to the outside viewer that is not as much in the know, often just seems like a mess of colors.

Back to Smash - I dont think its depth in Melee results in tough time for viewers - its pace, and excitement are contagious I feel. My brother, who's a casual eSports fan, but has no idea about melee - will watch and get excited while I am watching - and he's not getting excited over the "wrong" things - those technical bits often lead to amazing passages of play.

With Smash 4 having a lower cost of entry - it could be positive in a few ways - more players often leads to more viewers (5 new players, 1 goes to tournaments, hopefully the other 4 watch it) - which could lead to more branding interest - Smash 4 is a great way to back door more players into Melee.