Interesting that some people seem dead against the technique of including options but saying pro only when someone tries to use them. It seems to me that's very common with the freemium model outside the WordPress ecosystem.

For example, Feedly has a link in the menu saying "Integrations - New". When I click it, I'm taken to a page saying "Do more faster" and talking about IFTTT integrations. If I click the link to "Get IFTTT integrations", I'm taken to the sales page to purchase the pro version.

This model happens across numerous freemium services and mobile apps. I'd go so far as to say it's the most common freemium pattern, if not a 'best practice'.

You know what? If they provide value to me (like Feedly does), I'll use them. If they are close to crippleware, I won't. I think if people are unhappy with how it's been implemented in WordPress products, then it's probably because the developer got the balance wrong.

Personally, I like what the Theme Review Team are planning, except for the options behind a paywall one. I'd leave that to market forces: Those authors that go too far will get bad ratings and people will stop using their products, those that get the balance right and provide value to all their users will thrive and be able to follow the 'normal' freemium model. Is that too idealistic for the WordPress world? Seems to work elsewhere.

Disclaimer: I do have a plugin that has a checkbox that's only active in the pro version. Most people don't need it and can use the plugin perfectly well, but the few that need it can clearly see how it's going to work. It's in the documentation too, so they know what they are getting into before they install it (if they read the documentation!). I've had zero complaints, presumably because the plugin is providing value even without the pro version. But anyway, I have skin in this game, which may be colouring my judgement - so there's that! :)