Why in the new series there has been 3 regenerations in the Tardis without incident but this time it causes the whole place to explode? Theories please

The theory goes that the doctor and the tardis are linked, and this was the roughest regeneration, as 10 didn't want to go.

Cos the Doctor held his regeneration to 'collect his reward' and when he did start it the radiation blasted out.

That or the TARDIS set looked cheap and tacky and Moffat wanted a chance to replace it for the new series so RTD did his usual trick of just doing something with no explanation

I think the regeneration was more powerful this time because it had to eject the absorbed radiation from his body.

I assumed this too. I suppose it'll be explained at the start of the next series.

Because the TARDIS sets are getting old and Moffat wanted a new look for his tenure.

Or, people are still blaming RTD for everything they don't like even though it was established months ago that he wouldn't be writing anything for Matt Smith and what happened in the regeneration was up to Moffat.

I can't wait until Moffat starts doing things some people dislike, "Well obviously it was in the contract RTD forced him to sign when handing over the show."

maybe it was because they wanted to give the regeration sequence a sense of worry for the doctor, oh dear the Tardis is crashing, will the doc be able to bring it down without too much trouble, and of course it gave the script writer the chance to put in the line, "what was i doing? something really important! oh yeah! CRASHING"
which wouldn't have worked if the regeneration had simply caused a light bulb to pop.

Scenery chewing caused the set to fall apart.

OK my theory is that they rightly knew the Tardis really could not withstand the scrutiny of HD they took an nice opporunity to rebuild it.

And they really made the right desicion - it looked awfully blue peterish.

I still stand by what I said, all previous times his hands were never pointed at the console, this time however, along with the power of this Regeneration, he accidentally pointed Directly at the Console so the energy was shot directly into that.

Because the new series will be in HD and they need a new set..simples

It's taking a cue from The X Factor.

After the singer has finished singing their song, they've sang their song so amazingly well that the stage explodes with pyrotechnics going off all over the place.

It's just means that the Doctor has done a really good regeneration.