Only issue is "top 8" in na is going to have some huuuge variance in the beginning lol
Insofar as the top 4 seem a good tier above any other competition they might run into. So it might be hard to incentivize sponsorship of lower tier teams when relegation is a for sure thing. Plus top tier teams have low incentive to scrim unknowns, so the latter will be learning trial by fire style, could make for good storylines tho
I think this kind of a thing will drastically improve the talent pool over a year or so time because good players won't have as much incentive to retire/quit and amateurs will have more motivation to improve.
Running an esports scene the way DOTA works is just silly for most organizations as if you can't get your hands on a top-4-per-region, tier-1 level team, you get zero exposure as you won't reliably play in majors or TI. The same thing is true for HOTS. A great example of this is C9 not having a DOTA team since their team with EE split after TI5. They didn't have a team last season and haven't picked up a team for this season yet either.
The way DOTA is set up gives players a lot more power/value and you see this manifesting in player-owned teams like Secret and OG who are able to find their own sponsors. EG gives their DOTA2 team an incredible amount of attention, support and transparency because if they didn't, those players are marketable enough and good enough to easily find their own sponsors/partners and create their own team.
But none of that would be possible if the strong viewership and massive prize pools weren't there.
HOTS really needs the organization/sponsor support right now to provide additional money and stability into the scene to attract more outside talent and motivate existing talent. With more talent comes more competition, and with more competition comes more fans. So I'm really happy they're going to a league system, and I think it will help the scene tremendously.