I agree that you should consider ditching the DVD for a dedicated CDP. I think then you would be more likely to find a substantial improvement, even with a modest integrated.
If you acquired, say, a Rega Planet and a Rotel or Creek integrated, I think you would be pleasantly surprised. As for the Krell, it's a pretty good value on the used market, but I have not heard it paired with any of your other components.
And don't skip on speaker cables and ICs - many have fallen victim to the folly of trying to save $$$ that way.
If you acquired, say, a Rega Planet and a Rotel or Creek integrated, I think you would be pleasantly surprised. As for the Krell, it's a pretty good value on the used market, but I have not heard it paired with any of your other components.
And don't skip on speaker cables and ICs - many have fallen victim to the folly of trying to save $$$ that way.