I played pure Bard 20 spellsinger on Lamannia and it was very effective. I decided on live to splash in 2fvs and 2 rogue and I find it to be a significantly better build for me, although if save requirements go up I would consider switching to pure bard for the higher DC.
https://www.ddo.com/forums/showthrea...0-Exalted-Bard
The link includes a link to Lamannia with my pure 20 bard caster which was very effective, but less survivable than my current build. I would probably do the enhancements for a pure 20 bard a little bit different than I did on Lamannia after extensive playing experience on live.
The 2 rogue is for evasion and makes a huge difference in EE. My reflex is around 70 and there are only a few quests/raids in the game where that isn't good enough for a no-fail save on EE with epic reflexes. Both U21 raids, Haunted Halls, Brothers of the Forge are about the only places I noticed my reflex save being insufficient. I can tank the stormreaver in EE FOT no problem.
The 2 favored soul is very helpful because I decided on light as my primary with sonic and fire as secondaries since the EA destiny worked so good for me. The sp regeneration is not as good as you would get with a divine or shiradi caster, but it is still significant especially with the light spells and lantern ring.
The biggest problem I have on EE is my 50 fort save. Depending on the party and quest it can result in multiple deaths. My worst case scenario is What Goes Up EE where sometimes I don't die, but once I died 6 times in there - 4 due to getting turned to stone by the end boss and twice due to sonic stuns. That is partially from going with only 12 con as a drow and partially because I invested more heavily in reflex save (1 twist and epic reflexes vs. no investment in fort save). The fort save issue is only a significant issue in WGU EE for me, although there are also a few quests I won't attempt to solo because of the fort save issue. In parties it is only a problem in WGU EE.
Good luck with your pure bard build. If you come up with any good ideas please share those - there aren't many of us that are trying spellsinger which is amazing to me because they are so good.