Your loves of Ex-S and its variations knows no bound  while i do love Ex-S as well but Deep Striker chances are slim just like Nightingale. In the novel, it was not actually made and existed just on paper, thus it has never actually existed just like GP04. In that regard i'll actually said its chances are even lower then Nightingale. Even if Bandai could recycle some frame, they still hav to make a whole new set of arm, "leg", chest, and BFG. Its current prices is already in the upper echelon of their respective grades, with Deep Striker it'll cost even more and i dun think Bandai would venture into that. Not to mention its design is abit unbalance, without any stronger support (ie die cast or redesign or something) the sholder cannon would probably just flop around. Plus just like Beltorchika's Children, Sentinel ended ages ago and it was not translated nor release outside of Jpn (officially anyway, fans translation does not count). Recent trend does not look good on such kits with such a history. Just like Nightingale, ur only chances is if there is a sudden resurgence or a remake of Sentinel and how long is the hiatus between the end of Age and beginning of new series and also how desperate Bandai in those times is since there is plenty more other kits Bandai could make that has potential to generate more $$$$, especially all those obscure, easily reuse design mecha porn that is Unicorn epi4. If anything, i'll say the other variation of Ex-S (the 1 where the feet is blue instead of red and the orange is black) has a better chances then Deep Striker, at least that 1 is just a recolor.

I kno there is a fix figuration of it but Fix Figuration is abit weird in their releases, even stuff like Xii and Penelope from Hathaway Flash was made i couldnt figure out its pattern.