I am also a f2p(less than a year since I started playing the game)and I don't really like pvp(I hate this speed race)but I have 111 heroes and right now I have 10k skystones and 375 bookmarks

All story stages are cleared,automation tower too and I am at abyss 90

I only try to get heroes that I really want and I can see that they have multiple uses(not just counter this or that in pvp and that's it)

The only heroes that I get from banners are

Roana - really useful for the counter\extra\dual attacks mechanic that is very often found in pve

Dizzy - really useful in pve

Lilias - I use her a lot in pve

Yufine - I want to use her but I have no gear

Charles - same

Kayron - same

Diene - same

Vivian - same

My problem is not skystones or bookmarks but gear and charms(conquest points)to upgrade the gear

I can do only hunt 11 because I have no gear and the game refuses to give me good gear

In almost a year time,I have only 7 geared heroes(some of them need better gear)

As you already said story content is way too easy and can be cleared fast, but you want SG to make more story content? You want them to stop releasing heroes for months!? For what? You're not supposed to get every unit specially if you're F2P even if you do you probably can't gear and mola them anyways (F2P btw **** it up)

Episode 3 should be near release, maybe next stream?  They already release GG collab after end of EP 2 to buy time because new EP need to do many new story, monsters, backgrounds, NPC and heroes.

About time and bookmark since Q4,2019 they release new non ML hero only once a month except limited heroes (GG and Cerise).  So you normally have a month to farm BM for each hero.

New units means more $ for SG, of course they will prioritize cranking it out, those people need money to pay their bill too you know.

"I choose not to play this game as it's intended because I have performance anxiety and would like your development cycle to circle around my needs."

If you give time for f2p to get ss and get a unit let's say what 4 months from now is the same for whales. 

Whale: oh a new way to farm ss without spending ss!! Perfect 👌 

F2p: wow I don't have buy ss to get a hero!! 

SmileGate: how are we gonna make money? 

SmileGate is a company a gaming company makes mobile games why would they stop making heroes one of the factors to make players buy ss on stores? Is a good idea that benefits only the player base not the dev base. 

Let's make story content 

OK 

How are smilegate gonna make money if there's no hero revenue? No profit, no money, how are they gonna feed their families? Less hours, prob terminate a few employee from E7 dept just to keep normal paychecks flowing. 

Totally a player benefit and totally bad for the devs. Stopping hero releases for months will also make it difficult for devs to progress in E7 projects / newer content as there isn't enough money to generate in order to pay them. 

Yea that's why packs and stores are there! 

First and foremost, not all free to play individuals are in the same boat as you when it comes to Skystones. You should always have enough Covent Bookmarks/Skystones before you pull for a unit encase you might have to go the pity. SmileGate can make new units and bring in new stories at the same time. SmileGate should not deprive other individuals of something based on a personal request.

If you're F2P, you have to properly think about how you're going to spend, or not spend, your resources. Not just spend as you get them. They give more than enough SS and BMs if you're spending wisely.

Like Ikukotsu above me said "You should always have enough Covent Bookmarks/Skystones before you pull for a unit encase you might have to go the pity." and if you don't like playing like that, then spend some money.

The pace of new heroes and new story has been the same for several months now. The only hiccups to story have been for holiday events and the collab, which is always going to add a small bump in story progression in any game. This doesn't effect heroes/units because these aren't dependent on any story elements. Even so, they have announced there won't be any ML 4*s for a while, so there's that I suppose. Story has, and always will, be slower for the mere fact that they also need time to release all the relevant heroes as well. 

Nevertheless, there is a clear cadence to the release of story content. I'm not a PvP fan either, but you know what, that's just the kind of game this is; always has been. You can either deal with it or leave. I just do what I can, and that's it. 

Really want more lore over more packs...