[...ideas on releasing the lockstep of defenses/attack bonus/hitpoints/damage...]
Honestly Eamon, the problem with your "issues" with 4e solos is that you haven't really done anything constructive. I think you're making mountains out of molehills and then we're not seeing where anything NEW is being added. At the very most generous it is a complaint without a remedy, but honestly if you're players are so focused on the mechanics of the monster that they're having problems believing in it then I would suggest that the issue is largely with the presentation of the challenge. There's very little else for the players to pay attention to if they are hung up with a save bonus and whatever.
I'm seeing this in games I play in as a player. The solo mechanics are so overwhelmingly obvious tactically - and obviously
relevant - that it's not a mistake to recognize them, it's a necessary conclusion that follows from their design. Having 5 times as many hitpoints, odd extra action attacks, weird otherwise almost never occuring resilience to all effects and stuns/dazes in particular - these commonalities bind solos more strongly to each other than to their fluff.
Let's compare this to 3e spellcasters for instance. Spellcasters in 3e were often a first target and exceptionally threatening not because this was some fluff agreement - the mechanics meant they were less predictable, often less hardy, and frequently quite dangeous in surprising ways. Now, you could fluff that, and still tell the same tale - but it's no longer necessary in 4e. Spellcasters are no longer overpowering nor their effects much less predictable than primal or martial classes. Nor are they necessarily less hardy. Fluff works best when it tells a
meaningful story. Now, people think in terms of soldiers/defenders, controllers, leaders, etc. You believe in these names because in the game they're no mere myth, they really matter.
No amount of brilliant fluff will hide the fact that solos mechanics are very similar to each other. People will respond to the
solo - because it matters. When fluff and mechanics match, the harmony of the two works much better that when they don't.
Try giving them other things to think about and create more variety. Don't make your goblin badass a straight up goblin. Make him Mokrug Goblincrusher, chosen champion of Maglubiyet who grew strong on troll meat. He wields the mighty club Elf Slayer and you meet him on the Bridge of Trials in the Laughing Cave (lots of climbing, swinging from vines, etc involved, plus a few interesting features). The battle involves getting past Mokrug so you can stop the goblin shaman from sacrificing the Blessed Child to open the Feywild Gate. Nobody is going to be noticing much about mechanics here...
That's a great tale, and I'd enjoy it. But 4e is a very tactically oriented game. Players
will realize it's a solo almost instantly based on the description alone. They'll adapt their strategies - which are pretty complex nowadays - to the tactical realities of the game. The good players will interject a bit of flavor into their actions. But at the end of the day, they'll be fighting a solo; it's just instinct to ignore the irrelevant.
There is a solution - don't use solos, or use them only very sparingly. The quintessential solo is the game's namesake; the dragon: use the solo template only on creatures whose tactical characteristics strongly resemble a dragon in-game. If you need a special monster with special abilities - don't base if off a template that is instantly recognizable and who's features will dominate whatever you add yourself, and don't undermine the fluff by granting illogical abilities for purely mechanical reasons. If the story doesn't make sense, fix it, don't plow ahead and pretend it does. Doing this isn't that hard; give the critter backup; consumable minions, a resurrecting crystal, or something else - and make sure the fluff for that exceptional ability is woven into your tale well before the actual encounter - preferably several sessions earlier or more.
People will listen to your story much, much more closely when they figure out all that fluff actually matters and will actually remains relevant in weeks and months to come. They'll enjoy but otherwise ignore fluff that has no purpose in your story.
