i Don't know how new this is, But i recently noticed that after you install Ubuntu MATE And open up Firefox you get a Nice Ubuntu MATE homepage instead of the Normal Ubuntu homepage something that most distributions don't do And i got to say Thats its Great! i Love it. didn't Spend much time Taking a look at it. But correct me if this is already implemented or not. the Site Should remember which Search engine you picked (using cookies) And the homepage Should Have The Option to change language Or if possible By Default if the site detects a Version of ubuntu MATE with lets say French Language. the site will automatically be french or at least give you the option to change. Plus to that 'system detection' if lets say you are running an older version it of Ubuntu MATE it would tell you That there is a New version. in a small box at the top.
Just my opinions and my thoughts on how to improve it.
Keep up the good work that's all i am saying.