I kinda disagree.
First, I don't think Kemco will stop giving us a game per month (and since a long while this is an untrue myth). This is how they do work - quantity over quality. They noticed that selling 10 small games within a year for a cheap price is better than selling within the same year 2 good games for a high price. The reasons are obvious - first, that 10 games will get much more customers, than just 2 games, and second cheap games are cheap and therefore much more people can afford them. Expensive games are expensive and only a handful can afford them. Especially with the mobile market, where people most often take an oath that they won't buy a game that costs more than $3.
About recycling sprites, I also kinda disagree. This is my personal view, but since the games take place in the Asdivine universe, it is natural that some enemies appear in more than one game. Also, I myself like to look at familiar stuff, familiar enemies and bosses. Like to see how many more marks the I-C-U enemy will get, or which bosses dropped from their position and became mere random encounter enemies.
About the battle system I think this is actually a plus that they do not change it much. With this, You can sit and immediately start playing the game. You don't need to learn it, because You already know everything. You know how to craft weapons, You know which status effects are cool, and which ones are not. Personally I would love if they would stop changing the icons between the games, and start using the standard ones. Because for example in Istria, in Hearts and in Hearts 2 we have different icons (and in English Istria even different names...) for exactly the same effects. This is especially pretty annoying for the Japanese games, because each time I must learn what icon means what
.Plus, the most importan thing in the games is their plot, and in each game it is always different
.