I just reread issue #7 and it didn't hold up as strongly as I remembered. It's a little on-the-nose, both with its message and with the way it's put forward. I think I found it cleverer and more incisive in the past than I do now.
(It reminds me slightly of Spawn #10, the issue about creators' rights by Dave Sim and Todd McFarlane. It's maybe not quite as beat-you-about -the-head with the concept, but topping Sim and McFarlane in that respect is probably asking a lot!)
I do admire the message of this issue, and think it's still relevant in today's comics landscape. I also like the way it doesn't seek to denigrate those British Invasion creators (except perhaps to suggest that their 'deconstructions' of the traditional superhero maybe weren't as clever or as necessary as they might have seemed). Instead, it seems to suggest that we recognise them but aren't beholden to them, and we don't let their influence become stifling or suffocating to the point that new generations can't move on to create their own new waves of ideas.
Most of all though, it doesn't really feel like a strong Planetary story - or at least, not at this point in the series. It feels like a return to the template of the earlier issues, with the Planetary team more as observers than active participants in the story, giving Ellis the chance to play with the concept at hand without worrying too much about the series' overall shape. After issue #6, a story like this feels like a bit of a backwards step. Although there are still some nice moments (that make a bit more sense in retrospect), like Jakita's sadness at Snow's comment about how she's constantly surprising him.
There's good stuff in here - hearing Ellis moan about Thatcher is always good value, and it was maybe the case (especially at the point when this comic was published) that a new generation of creators needed to move out from under the shadow of Moore, Gaiman, Morrison and Milligan. But like @Tom_Punk says, it's perhaps just too self-referential a comic to really pull it all off without seeming a bit navel-gazing.