If you want a layout with minimal changes, you could try something like Minimak.
The best "quick fix" to Qwerty IMO would be to have the most common consonants on the two home index finger position - which could be achieved with T-F and N-J swaps. But, on it's own, that does nothing to improve bigrams, and arguably makes TR worse, which leads to the need to have something like this, perhaps a viable minimal-changes layout:
Q W E F P Y U I O ;
A S D T G H N K L R
Z X C V B J M , . /
Home "row" would be ASET NILR in this, longer middle fingers reaching up to the top row. Note we still have the dreaded DE and LO Qwerty same-finger bigrams though, but at least the most common keys are better positioned, at a cost of only 6 letter keys moved.
Minimal changes sound like a good idea, but if you're going to take the trouble to be non-standard, in all honesty you might as well go the whole hog and pick something fully optimized, and preferably, tried-and-tested by many happy users!