Demon's Souls is still today the best Should game made by From with innovative features not found in the late copies.
It is one of the most asked game from PS fanbase... so something is wrong with your claim.
Even if Demon Souls is a game I have a lot of love for and I believe will get a remaster at some point I just can't see it being BluePoint's next project especially if they're saying it's a big one. Souls games have a very hardcore/dedicated fanbase but I would still say they're quite niche without a broad appeal. Is it that asked for, or are they people asking for it just the most vocal?