Character Balance is NOT NEEDED - Role balance IS
Please do not waste time trying to balance character classes/races/destinies as IT IS NOT NEEDED. There is NEVER going to be equality between the killing ability (which is what I assume you mean by 'power') of all builds. D&D is not a game where this type of balance has ever been possible or even desirable. Each character is not supposed to be a killing machine, they are supposed to be able to contribute to the success of the PARTY using their skills/abilities according to the role they play (healer, trap monkey, CC etc) not have everyone aiming to be top of the kill chart. If all that people desire is to be death dealers then everyone would simply play monks - or better yet play WOW.
D&D is about dungeon delving with a party setting out to achieve a goal - not about who kills the most. A healing spec'd cleric who keeps his party alive despite overwhelming mobs of monsters but does not achieve a single kill is many times more valuable (i.e. powerful) than an assassin that can kill with a glance.
DO NOT seek character balance - that is for lesser games which promote the stupidity of PvP (something which should not even exist in DDO). What you should be seeking is balance between the character builds which fulfil a similar ROLE so that each can feel they are able to contribute to that role despite their personal preferences for race/class/enhancement/destiny combinations. e.g. a healing spec'd FS (currently not possible - a failing in role balance between divine classes) should be able to achieve as much positive energy as a healing spec'd Cleric, and a Rogue/Artificer should be able to achieve a similarly high Spot skill as a Ranger (at the moment impossible as the Ranger has Wild Instincts on top of everything else while Rogues/Artis have no obvious way to boost their skill that high and thus can easily miss traps in EE dungeons).
Seek balance for well put together parties filling by characters that target a role, not individual players out to top the kill count. DDO is a group game and should not go the path of dumbing things down to the point where everyone solos their way through using the flavour of the month killing build.
Balance = Time & Resources
Why you would even approach this topic with the disclaimer that you don't have the ability to give this the attention it deserves baffles me. Balance is the core of the game, and varied/interesting synergistic possibilities keep people around. If you are going to alter this then you run the risk of alienating players and I have no desire to lose more friends as I have in the past because of thick headed decision making and as Seph said "band aids over bullet wounds..."
The whole issue is rather simple in my head, and goes to the heart of running games, be it on a table top or over an internet connection. I've been a DM in my local group for seven years and if there was one lesson I could extract from my time it is as follows
"If you force players to relinquish something you have already granted them or retroactively diminish a power level your PCs have achieved you are doing it wrong."
Don't mistake this for a "game is OP nothing we can do about it now" attitude. Instead the game, at least at EE has evolved into something that people still extract a lot of challenge and satisfaction from. On a stat level yes it can be hideously inflated, but that's a natural progression that power gamers will find themselves in. Instead of just chopping away at a given destiny spend that dev time giving us another option - even ONE MORE DESTINY that can compete in terms of viability is infinitely preferable to the nerf bat. As creative people isn't that far more satisfying that going back on what you have already brought into existence?
Some other people have commented on it, but I think there is an element of torch and pitchfork community mentality here. A lot of players have demonstrated quite a level of ignorance as regards some of these classes - especially shiradi. While yes this is indeed a powerful class, it sits behind an enchant specced draconic wiz with good spellpower by some distance. Take the two into EE Storm horns and the wiz will clean up while energy bursting held mobs - there's no contest. That's before they even try insta death spells.
Master's blitz? If anything this needs a buff in my opinion. Keeping this up in a full raid group of pugs is near impossible - people just don't want to prep mobs/refrain from killing and this encourages a really reckless style of play. In my opinion it requires an expert level of communication which is something that we want to encourage. I have never once in the year or so that I've come back to the game post MOTU thought "oh that darn blitzer is so OP." Not once. If anything I feel blitz should start with 2 stacks/3 if under 50% HP. Asking someone to sit at 400hp on EE if even for a few seconds while wading into melee is a death sentence on harder content. I'd be happy with a 50% reduction in damage in favour of more stability. In addition your fix to portals and charges is arguably worse than before - now we don't know whether going through a portal will adversely affect us or not.
I remember before I left the game in 2011 listening to a DDOcast round table discussion where Lessah spoke about the "current state of haves and have nots in the game." This was an issue at the time and is an issue today. It will be an issue in 2017 if we are (with any luck) still going at this. The game has been homogenised (at least in terms of loot) somewhat since the days of 20 cap epic grind fest, and this has largely been effective, but there are always going to be people decrying the power of others. Give them a viable option as an alternative instead of reigning in the ability of others to combat 500k hp giants.