I think it mostly have to do with how much work it takes a game to translate and personal preference. Most of the time, if it's just something done out of charity (no money gain), a not-so-experienced translator would prefer to translate games that are easy to translate regardless of its quality whenever he/she feels like it. Some may put on bigger effort for bigger and higher quality games if they're experienced enough and can translate them through the end (though I saw many people abandoning big project due to lack of devotion).
Personally, I understand the feeling, I myself am trying to translate a game that is easy to translate (RPGMV) by just using Notepad++ and Libellule's Clipboard to hook the text. Since I've never really translated any games yet, and since I'm not a native english speaker, and most importantly since I don't have ANY knowledge about japanese language aside from something like "baka, onii-chan and stuff", I mostly choose jp games that are mid-quality in term of content and story-telling.
What I'm trying to fully translate (definitely not machine translation in sakuragames style, but not quality translation either) are two games that are "Emiliana - Holy Lady's Demonic Convenant -" and one of 'Orange Piece' RPGMV games. When I get bored with one of them, I switch to the other, then vice versa and so on. Well they're kinda big in term of content and story-telling, but the main reason why I took them is because I really loved the art, and the story itself was decent at most. When will I be done with the translation? Whenever they're done lol.
My personal opinion as a wannabe translator.
