I really don't know if this is so unlikely. Lets lok at a few things
Burning Shops:
Dev went rushing round looking after many of the shop-owners on the night and in subsequent weeks. Obviously he got calls from many of the shops and went round to get the people out.
As soon as he knew Maya was with Sunita he rushed back there, and was subsequently knocked out. On the night there is nothign to suggest that he didn't check people weren't OK or indeed safe. After the event we only saw him deal with Sunita, but again there is nothing to suggest that he didn't pay some attention to his other shops and indeed the workers there. WHile Sunita was scared in her flat we didn't see much of Dev at all so why are we all assuming that he didn't visit the other shops
Womanising Dev
Before getting together with Sunita Dev was a bit of a smoothy lets admit it. A little bit of Deridre, a little bit of Tracy... he made Lou Bega look chaste. There is nothing to say that he wouldn't see a woman for a while and then move on. He has provided for them, shop and flat, and has no necessary connection to them. He clearly wants a son and has not got one as yet. Dev is looking for his male heir.
Dev's voice:
well even I have no explanation for this...
Sunita does love Dev because he delivered her from teh pressure of her family and her arranged marriage. Fair enough he has his secrets behind him, but I don't think that it is completely unlikely and if you were asked who is likely to have a litter of kids that we don't know about we probably would have said Dev second after the original lothario Mike Baldwin.
The future story won't be Dev getting to know all of his kids, I eckon only Amber will stay around. It is not exactly full of holes the plot. It is one that perhaps has been well hidden by Dev, but is neither impossible or improbable given Dev's background and character.
What gets me is comments that are merely provocative and unhelpful. If you are going to stop watching a story then either do so, or provide adequate reasons for bothering to come on and tell everyone about it. Why on earth is "Corrie a complete joke now?" such commetns I find are not provided with the intent of facilitating conversation but instead to promote the disquiet that has been creeping in on the threads for a while now.