Seriously. If you have a customer who has demonstrated a willingness to spend on your game, placing increasing disincentives to that spending in their path doesn’t really seem like the brightest idea from a business perspective.
I mean, don’t get me wrong. I get it, I do; because Hero Points can be earned as well as purchased, and high-end players can earn those points through PVP and PVE finishes, capping roster slot costs could result in high-end players - presumably those most likely to be ‘whales’ - not spending on roster spots, which are probably one of the two biggest sellers for Demiurge/D3. The other being additional character covers.
So you know how you address this? leave the existing roster spot model in place (no wait hear me out guys) and for each account each month, have a ‘one-time’ sale that includes a roster spot with the purchase of Hero Points. You’ve got five tiers to work with; granted, the $1.99 tier is probably too low to include a roster spot, but you could do a spot + 600 Hero Points at $4.99. Then you have three other tiers to play with to add another roster spot bundle. You know (presumably) how many characters you plan to release in a month. If it’s two, you could put that at the $19.99 tier. If it’s four, you could put that at the $49.99 tier.
And by leaving the existing system in place, the Hero Points your customers purchase are still going to get spent on SOMETHING…and maybe that something is an additional roster spot over and above the one they got with their purchase. By making it a one-time thing each month, you allow casual users to keep up with the roster crunch (at least to a degree) without having to spend hundreds on Hero Points, and you incentivize the purchase of Hero Points across the entire community. There is quite literally nobody who plays this game who says “yep yep i have all the roster spots i need why would i ever need another”
To repeat: the Hero Points getting purchased to get the free roster spot each month are still going to get spent on something, whether that’s shields, tokens, covers, or…yet another roster spot. People who are buying a Stark Salary each month are probably not going to begrudge an extra $5 on Agency Expenses if it comes with that extra roster spot; nor are they going to forsake the Stark Salary (which they presumably are purchasing because they churn through that many Hero Points in a month) because they bought the $5 package instead. So at the high end, you’ve got a 5% increase on ROI, and below that tier, players who can more easily keep up with the roster crunch are players who are going to feel more willing to spend.
TL;DR: you’d see an increase in overall revenue, and even if that revenue doesn’t continue to get spent on the most expensive part of the game (for most), the Hero Points have to go SOMEWHERE. You get a modest increase on ROI at the top and potentially increase wider participation in the game economy by those at the bottom.