GW1 and 2 did very well. GW1 in fact did so well to EA's apparent surprise, they decided to make GW2, which also did well. BfN probably still made money overall, but not as much, as is made plainly obvious by the fact that GW1 was supported for 2 years, GW2, for almost 4, and BfN for not quite one year.
I don't hate BfN, in fact, despite the issues that still linger to this day, I actually like the game, but barring some positive changes, it's overall not as successful as GW2 is. The issue is, my understanding of why they made a new shooter was the player retention they've been seeing of both GW games that really enjoy these games, and BfN has irritated a lot of the very playerbase they wanted to keep and expand on by making BfN more like its competitors. This has obviously not worked as well as expected.
A new game would likely go along the GW3 route. They may even drop the new BfN characters just to free the game of the stigma of BfN among a large swathe of the GW playerbase and the fact that it was the only PvZ shooter to lose support so quickly.
Looking at your list of problems @SundropDot ;
1- GW1 is still an unbalanced mess to be honest. One of the reasons I don't revisit it all that much is that if you jump into a game, half the zombie team is going to be Super Commandos, abusing the overpowered extra ammo upgrade they get. And GW1 has the least base characters and variants. I'm not excusing this, as I'd prefer the games to be more balanced, but because there are so many options, they tend to shake out fairly well in teams of 12. One of the reasons GW2 kept my interest so long was that it had so many variants to play.
2- I'm going to say that they will likely examine what worked and what didn't as far as abilities and other characteristics go and then use what they like the most and hopefully what plays best. For example, I'd vastly prefer a GW1 or 2 Engineer over the BfN version (ability-wise anyway), but they may hybridize him for the new game.
3- Sprinting is something I deal with but if it disappeared I'd not worry about it. They really can use different base speeds (and yes different sprinting speeds as well if they keep it), to balance characters and give them their own feel. As for team-ups, I love the idea but they would have to decide if they want to keep that or not. They'd have to balance Acorn/Oak to Cadet/Station at the very least.
They definitely need damage attenuation (dropoff) to come back!
@Iron_Guard8I feel like they would drop the bfn classes because some of them arent even that interesting from a gameplay standpoint: electric slide literally uses a scientist ability but retextured, snap dragon outside of abilities is just a fire chomper with more range and lacks the ability to actually kill with fire, wild flower and tv head are just ai reskins and arent very unique outside of a broken spawn system which guts the flow of combat, acorn just feels like a busted imp, 80s without abilities is just diet hanzo, space cadet is just acorn but more broken, and nightcap absolutely fails at being a stealth character. Heck most of the redesigns in bfn feel like they're chasing the glorified and overrated vision of overwatch heroes and it just dosent work.
Battle arena had no players online and ranked was practically unplayable and the rewards arent worth it so it would most likely be left behind as well.
Sprinting is redundant if the base speed is enough: look up halo 2 vs halo 5 mobility comparisons and the sprint speed is literally just halo 2 walk speed lol.
