Someone once said (Knuth? Torvald?): One program should solve one problem.
On the one hand I'm with you, filling the addon-folder with small "one per purpose"-addons makes this folder - full.
But why should you care?
On the other hand, if you want to share your addons with the community, it's always best to provide small addon, someone will like exact one functionality and will not download your addon, because it is full of other features.
My PredatorBar is an addon, which will soon be split into different one (perhaps they will be modules), just because of this. I started putting into this bar some small things, currently I'm adding chat and tooltip-features. Would you expect such things in an info-bar addon? No, nobody would.
Lua is quite complicated when it comes to the creation of a frame. If you're creating multiple frames which share some attributes, XML is the way to go, just because of the templating-mechanics. And it's written fast and easy to maintain.
Offsets = x-coord, y-coord.