Mari IS quite adorable, and the poor thing needs contact. I... I'm in love.
she definitely needs to wear her hair down and behind her ears more. Her normal hide-behind-the-fringe thing doesn't do anything for her and the twin ponytails thing makes her look like she's trying to look twelve.
Let's not forget she's a construct by a guy, who's showing her symbolically, still 'hiding', still immature. If/when she busts
out of that shell, the makeover could be amazing. (See PennyandAggie for an example; I'm too lazy to find it.)
And as much as I and others adore her, I'm not sure Sven would be attracted to her type...? His 'dating' history has been consistently attractive, confident blondes, with Faye an attractive, confident personality. I don't see Svendog even sniffing in her direction. To me, it's an obvious, jarring, uncomfortable mismatch (as much as they both might enjoy/benefit.) Plus, Dora & Faye would inflict major damage and derision upon him, for taking advantage. Really, the power balance is almost totally one-sided, unfair.