Bungie gave us (excuse the pun) a game changer with Halo CE, Halo 2 and 3 built on that. This created a very strong IP that has been passed onto 343i.
I liked ODST and Reach (Reach is still one of my favourite games). 343i had a very tough job to breathe new life into an IP that had been concluded rather well. I think 343i did an outstanding job of doing this with Halo 4 and they should be proud of their work - as should Bungie, because in a very real sense what 343i do with the IP is part of Bungie's legacy.
Bungie did the smart thing by becoming independent at the cost of an IP that they had concluded. The Destiny Beta feels like they have taken the skills, knowledge and experience built up through Halo and moved it up a gear or three. I honestly believe that Destiny is the next game changer (sorry again). I'll be getting it in a few short weeks for the Xbox 360 and for the Xbox One when I get that console for the Halo 5 release Q4 next year.
But in answer to your question, no Bungie shouldn't even consider getting Halo back, they shouldn't live in the past. Trading on past success is generally not a good way to plan for the company's future. Destiny, however, will (I think) secure Bingie's future.