Honestly, probably not do it! It's a hell of a lot more difficult then I had imaged. The most difficult aspect I've found is expectations. My experience is selling on Themeforest so those not selling on there will have different experience than me.
I caveat everything I'm about to say in that many of my customers are lovely respectful people. But, there is a general problem with customer expectations and the marketplace in general.
Your part of a global market so you're competing with those who's cost of living is low so they can afford a lower ROR.
You're also going up against those who have spent years developing their framework and have teams of people developing it and teams of people offing support.
Customers expectations have been shaped by these things so support becomes much more costly then you may think. Customers will come to you expecting free customization, help with things that have nothing to do with your theme, and to be hand held developing a website when they have 0 experience using WordPress.
But the problem is other authors are offering these things so if you don't - you don't look good, if you do, you'll find all your profits are being eaten by support time.
The thing is with expectations is that if what you give is under there expectations they will be unhappy, they will rate you badly, ask for refunds and generally be miffed. The problem is the expectations have been set high by others trying to compete in a over saturated market.
Generally customers want all purpose themes, those are the ones that sell. But, because of how other themes have been packed to breaking point with features made over years, made by teams and make by those with a lower wage ( so can put more time in ) it's pretty difficult to meet the expectations that they will want from a all purpose theme. And the risk is that you won't be able to sell it enough times to get even close to the time you put into it.
On top of that, Themeforest do not listen to their authors they make things much harder then it should be. Like the fact they introduced 6 month support and a renewal. Problem is, that doesn't work. Because this support is optional and is not a subscription, customers will only renewal when they have a "problem". So what happens is your being paid peanuts work.
They also allow customers to rate even after the support has expired so you end up with customers using the rating system as a way of blackmailing for support for free. Or they rate you one star because, why should they pay for support? The expectation has been set that themes should be $49 dollars and come with unlimited support forever more no matter how many sites you use it on or wether it's 2 years later and you're doing a re-design.
You wouldn't install Photoshop and expect adobe to teach you how to use it, how to design and to add features just for you. But in the theme world that's a common expectation.
I'm considering releasing themes myself but many people have tried this and ended up on Themeforest in end because that's the place people go when they want a theme. It's disappointing as I don't want all my efforts to go to waste but I'm also not keen to throw good money after bad.