What features would make a WordPress theme perfect for IM?

Integration with autoresponders is definitely needed.

If for me, I'd look for squeeze page and sales page builder.

I would like to see something like OptimizePress and be able to load others themes into it.

Squeezes page creator, sales page creator, blog ext....

A full width bottom background or footer with out coding. A nice social network area with a Facebook fan page and not the profile.

Basically every feature you possibly can or willing to do.

What I would do is search for what the majority would want and not just from the WF. If you want a good product, you want to see what thousands are interested in.

I would search with Google keyword tool. "Parentheses" in Google search to refine the keyword. Search on other forums. Send a survey out to your list, Facebook, twitter ect...

It would take about a day to get a good idea on what people are interested in. Your surveys will keep coming in as well

If you are building a squeeze page, or LPs don't bother bloating things with Wordpress.

I don't feel this is the case.

Also most feature mentioned, you can get plugins for, you don't need them built into the theme.

The theme needs to be all about design for me. I can get "features" with plugins.

Sorry not trying to be a buzz kill, I'm just on Wordpress all day, and that is my feedback.

Your idea for design standard is good.

I agree with the squeezepage thing - multiple templates!

A semi-squeeze homepage, top third of homepage a video or ebook pic plus optin to right then the blog posts below that.

not enough of these around, maybe one I can think of.

I do a lot of WordPress development (plugins and themes) so here are my 2cents.

1 - This is true for any theme but make it easy for plugins/custom code to hook in to your theme and follow best practices for coding WordPress themes.

2 - Make your widget areas flexible and easy to set (think ad spaces etc).

3 - Test your theme with popular plugins and then you can market it as 'compatible with x, y and z plugin'. That's a great selling point as a lot of customers worry about whether their plugins are going to break with a particular theme. Important ones for marketers are the top SEO plugins, the social plugins (which add buttons for example), ecommerce plugins, membership solutions and caching plugins.

4 - If you want to go sophisticated you could try a page builder for creating salespages, squeeze pages etc but you'd need the coding chops to do that or you could find some existing projects to plug in to and create your own graphics for example to give it your own spin.

5 - I think for innovating on features, that's mostly going to be plugin territory and I wouldn't recommend stashing plugin type functionality in the theme itself (put it in plugin(s) instead, you can package those along with your theme even).

6 - Optimize for performance, as sites that load faster will convert better. Use graphics wisely and don't use graphics when you can do it with css. And again it's important to follow the best coding practices, for example plugins that do minification won't work properly if scripts are hardcoded (there are lots of themes that get this wrong).

7 - Make the theme responsive. That's a great selling point as well.

8 - Creating a really solid theme is a lot of work, very easy to underestimate. Of course, you'll always be able to sell a theme with good marketing, but if it's shit you will have disappointed clients ultimately. If you have a long term view, support is a huge selling point that has nothing to do with your theme design but is very important to a lot of buyers. You could add different tiers to your theme product with different levels of support which would make it interesting to marketers as well.