Anirudh, I guess complexity might be an issue. Most of these kind of features either track into wrong categories or end up putting everything in "Others".
Maybe, in addtion to MCC, if you let us manually define keywords and catrgories, and automate the categorization based on those, it might work reasonably well. And, the description can be the transaction name with the name itself being customised.
For example, I subscribe to Tutanota and Humble Bundle. Maybe I can say "If the description has 'tuta' categorize it as 'Service Charges' and name it as 'Email Charges'" or "If the description has "humble" categorize it as 'Gaming' and name it as 'Humble Bundle'".