Regarding gold...
That is highly realm and situation dependent. I've had precisely three characters who at any point in their life really had "surplus" gold. One of them was expressly created as an attempt to fill the coffers of House Bedwyr, and made a lot of money as a spy. One of them made it to a lordship in a completely peaceful realm with nothing going on, and the last is the Duke of a large city on Dwilight who only occasionally has surplus funds and those tend to get plowed into his religion or infrastructure improvements.
That's mostly because I've ended up playing in realms that are constantly fighting important wars where every piece of gold counted or on frontiers where there was jack-all gold to go around 
Consequently, House Bedwyr has the highest fame/family gold ratio that I'm aware of.
So, gold is one of those things that can depend on the place and time. It only annoys me when I see (for instance) the handful of people at the top of the realm leading 100 man units while most of the army is fielding fifteen or twenty. IC, I love seeing that in my enemies as it means I have a good shot at finding disaffected elements and it's incredibly inefficient. OOC, it bugs me, because that's the kind of thing that drives people away. Fifty vs thirty men is one thing, being a Duke has its perks. But 100 vs 15 is just silliness.
I can't speak for everywhere, but in Enweil I've often led 100+ men units while others had tiny units. But hey, the dukes were giving me gold to spread out to my army, and when I made offers for gold to the army hardly anyone ever replied. So I just dumped most of it on my own unit. Sometimes, people are really to blame.
And really, some of these people were often directly given cash, and we never saw their units grow, and as far as I know everyone in Enweil has a good enough oath to recruit at least a respectful amount of men. So meh. Ducal handouts were really just a plus, mostly to help whoever wanted to lead a TO unit (anyone could, they just had to ask), or to replenish units decimated in battle. And while I didn't have the gold to recruit such huge units by myself, my income as lord of a rural was enough to pay for their salary without need for supplements. And those were highly-trained archers from the best available RCs.
Hm, hey, remember when Chenier said that bankers were useless? We could give them some sort of option that could assign a portion of realm income first to priority recipients.
Like, the banker could have the comprehensive list of all nobles in the realm (except, maybe, the council, dukes, and lords, to prevent abuse). The judge and ruler already have similar lists in bans for the former and ooc bans and exiles for the latter. This would just have different mechanics and intent.
Basically the banker is notified of who needs financial aid. The banker selects a % of real income to be sent to those people, before all other calculations for realm income (or after, this is just rough idea). This information is public and can be checked under some page in the Information page, both to make sure it's happening, and because, well, this stuff should be public since it is the realm's stuff.
Yeah, it's unrealistic. But you know, I think I'd rather play a slightly unrealistic game than one that I do not like due to mechanics conflicting with realism.
There is no option you could give the banker that you couldn't give someone else. I also deeply dislike the welfare tax idea, but would not oppose a capped class-based tax from coming back.
"Welfare" tax is just so damn abusable. It's one thing to cheat yourself out of the property tax to avoid giving your gold away, but to then grab the gold of other more needy nobles? It'd be cheap. Needy nobles would get ripped off by the malign.
