Agreed that Davies is the worst writer for the series. That much has universally been established. If only Moffat could take the reigns.

As for the Earth thing, I agree...as do a lot of fans these days. Davies needs to get over his fear of getting out there. He stated in the beginning that he was fearful of not having enough SFX budget to convincingly convey alien environments. And while that may be true in comparison to movies, he needs to get a clue. This is tv, and I doubt anyone expects Lucas-level vistas. He needs to venture out there more and more. One of the reasons I love The Impossible Planet was because it was essentially as much of an alien planet that he's allowed the show. We need more, otherwise it gets ridiculous.

As for Tennant, I'm still mixed on him. My biggest gripe isn't that he figures things out too quickly. I understand they have to rush shit because it's an hour-long format. My biggest complaint is the damn sonic screwdriver. I don't know what The Doctor used to create this new version of it (since the original was destroyed back in Davison's era), but it must be made of "Beyonder" particles. The thing does fucking everything. It's ceased to be an accessory, and become a plot-prop to get him out of every situations, and accomplish every feat needed....if only because Davies hates "technobabble" and fake science. I hate to break it to him, but, the sonic screwdriver has gone far beyond the things he hates, and has become fucking magic. It's really getting ludicrous.

Tennant himself, and the 10th Doctor, really seem to shine under other writers. Not to mention, his first season didn't exactly have the strongest scripts. I've heard rumors that alot of the scripts were written for Eccleston's Doc before they knew he was leaving. You can detect this in some of the dialogue. Tennant seemed to be saddled with doing Eccleston dialogue, while converting it to try and fit his Doctor.

Finally, Rose with Tennant never worked for me. Davies was trying to hold on to the magic and chemistry Eccles and Piper had. It didn't work, and that was obvious. Now that I've seen The Runaway Bride, with no Piper, and Tennant finally given the chance to be his Doctor, I have found a glimmer of hope in his regeneration. Rose's departure has left the Doc reminded of how alone he is in the universe, and how alien he is compared to most every other human. Also, the aforementioned "dark side" is given voice and moment in this episode. Love it.

So, in the end, we'll see. I've never judged any Doctor on one season. To do so simply shows either severe impatience, or, an ignorance of the entire concept of how Who changes and evolves. Tennant will either grow and get better with this next season (and that's up to Davies, mainly), or, he won't and I'll just bide my time until we get a new incarnation. Simple as that...