Using D300 and need lens advise

Currently own:

16-85 VR - my best walkaround lens, never missed a shot with it.

105mm 2.8 VR macro - new addition, very happy with the images.

Tamron 28-75 2.8 - almost not using it since my copy of 16-85 performs better.

My Issue:

70-300 VR - this is where I'm having troubles. The images are not very sharp especially after 250mm.

I'm thinking to replace it with 70-200 VR II (and getting TC2.0 in the future if need longer reach). Tried it at the EXPOSURE this weekend (although with D800) and I was really impressed. I never had anything that sharp and fast auto-focus. I'm shooting a lot at home (using speedlights) so not really thinking of getting 1.4. Shooting kids outside activities - that's why I need telephoto lens and even though I can use 105mm but many times it's not long enough. Given the lenses I have will you make this upgrade or you will suggest anything else that I'm missing in my setup? I see a lot of good reviews for 70-300 VR and thinking may be I should just fine tune it at Nikon's...

Thank you very much for responses!

BTW - the other impressive lens they had which is planned to be released next spring is 800mm 5.6. According to their representative it's lighter than the 600mm 5.6.

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GimShim
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It is easier to stay out than get out.