1. Is the attrition/quit rate higher than average for mobile RPGs? I find that every week, there are 1-2 people from my friends' list who go inactive.
2. Reasons that I've gotten from those who quit:
(a) Fed up with the RNG/luck-based nature of getting heroes. Too dependent on lucky summons to progress and compete. "If there's only a 1 in 6 chance of getting the hero I want, how come they have a 100% chance of getting my money?" "I'd rather buy 4D Toto; better odds. 1.8% to win something; getting a specific rune is ~0.6%."
(b) Not enough storyline/quests to complete. Too repetitive in the event design. Get very bored repeating the same levels over and over.
(c) Arena too frustrating; F2P getting matched up with P2W no fun at all. Not to mention that if you didn't allocate your resources in specifically just two main ways (among the many, many team comps available) or were lucky enough to roll the right heroes in a timely manner, you can forget doing well in arena, even if you are matched against a player who spends the same amount of money as you do.
(d) Encounter design/mechanics frustrating/not fun unless you are lucky enough to have the right composition as per (a).
(e) Hero design/power creep -- newest heroes make old ones obsolete too quickly. Valiants are said to be the best heroes but they are not in practice because it takes too long due to their rarity and cost. It's easier to max/optimize the stats for other 5-star heroes due to greater availability for limit break and pixies.
(f) Irritating pop-up promotions that come up without warning -- have accidentally made purchases because the buy button is in the same place as the other buttons, especially when repeating event quests.
3. That being said, the game's good points are:
(a) The graphics, art and music are first-rate! Costumes are a nice idea.
(b) The basic premise and gameplay mechanics are great and very promising/fun! Reminds me of the best features of Final Fantasy Tactics, Heroes of Might and Magic, etc.
(c) Generally well-designed UI and game flow.
(d) Coding quality is high; e.g. unlike many other games, this game doesn't give problems/hiccups when you have to switch to other apps on your phone or when a call comes in.
(e) The game difficulty ramps up well and the developers make the game generous and rewarding for beginners in the first month.
(f) Able to progress decently well even if you are F2P
I do have some suggestions for improvements but I'll make a separate post for that.