Oh yes - I always house rule games I run. Some a little, some a lot. 4E is, currently, one I house rule only a little (as in a few rules but some of them are pretty 'big'). For example
Extended rests do not restore hit points, only surges. Thus, as has happened on more than one occasion, if you end a days adventuring low on hit points and with no surges left you will, after a night's rest, gain back all of your surges but still be down a few hit points - which you can recover by spending a surge or two. Thus the extended rest is not the 'instaheal' is used to be you can have some lingering effects even if it is 'only' a lost surge or two.
All (or nearly all) monster defenses are reduced by 2. With the big HPs most monsters have hitting every round doesn't really slow them down. I also beef up the monsters damage in some cases.
'Soldier' role monsters shall not be used. I hate soldiers. I really, really hate them. If I simply must use a soldier it is never higher level than the party and never a solo :shudder:
I have a few more but they are more campaign/group specific. I am still wrestling with the minion question but I think I will do, for Paragon tier and above, the 'first hit bloodies, second hit kills' route.