I don't know how to say this, so I'll just come out and say it:
I'm going to replace my players' d20 attack rolls with 3d6.
Since it's my first time DMing 4e, and we've decided to start at level 5, I reckon there are enough differences already that making one other change won't cost too much in terms of organisation. Sure, I'll have to balance some of my encounters a bit differently, but I did anyway (I've never made up a l5 encounter before).
I've decided arbitrarily that critical hits and misses will work thus:
I guess there are loop-holes and questions, most of which can be sorted out at the table, like: high crit weapons (which will probably add a [second] damage roll on 16+); or what happens when you roll 3 and fall prone while flying; etc. If/when we find good resolutions for these and other issues, I may share them.
I'll keep the d20s for the regular ability checks, since.. well, who cares, really. And I might let Elite and Solo monsters roll 3d6 for attacks too, depending on the situation, since that will add spice (and hopefully fun) to the fights. Apart from that, regular 4e all the way, I guess, and we'll see how it goes.
First game tomorrow night.
... Matty /<