I can't comment much about recent dramas, last 2-3 years, b/c i took a break from K-dramas and just returned to watch SH:Ryeo!
I understand and agree w/ some of the things you mention...
--- Formulas/Cliches: I can't comment about the boring love, or weaker 2nd lead ... But, I can tell you that I left K-dramas b/c I got tired of the cliches, the formula writing, the over-used tropes.... As a fan of romance, I especially felt unsatisfied w/ the overly idealized love, especially the nonsense about some ridiculous obsession w/ a 1st love from childhood.... and the lack of realistic passion.
--- Recent changes: While oh hiatus, I heard great things about Secret, KMHM, Secret Love Affair, Bad Guys, Incomplete Life, Signal and Six-Flying Dragons ... I still haven't seen them, but I noticed that there seems to be more originality, more venturing outside comfort Zone of formulas, trying sensitive subject matters....
Upon my return, watching SH:Ryeo, I was immediately reminded why I left K-dramas... the shallow sentimentality, the vanity ,and the obsession w/ choco abs and plastic surgery.... Not to mention the cliches, i.e. the poor girl running from debt collectors or the clumsy, childish yet cheerful heroine, etc...etc...
But, I was also reminded why K-dramas are so popular, something about their formulas has universal appeal ... Due to that success, producers play it safe and replay the formulas to ensure popularity ....
--- The System: idk what happened to the shows you mention, but I can tell you that S.Korea has a system where they shoot about 3-4 episodes before drama goes on air, and continue filming as the drama airs... Sometimes, scripts are not yet completed, often they undergo changes as more episodes air ... and sometimes, there is a change in the lead b/c fans prefer the 2nd lead actor (Queen of reversals, Empress Ki, etc..) ... Empress Ki is a perfect example of how a perfect script (up to Ep23) underwent change and plot became a bit chaotic, lowered quality....
Recently, there have been many complaints about this production method and how the industry treats its workers... So it is undergoing change... SH:Ryeo for example, is pre-produced.
--- Romance and Passion: Now, as to the boring or love w/out excitement, I much prefer the way the Chinese do romance... They keep the Romanticized Idealism of true Love, but without the formulas and cliches, and they combine it w/ the realism of J-doramas, without the stark pessimism.... Although idealized, romance develops in a more natural way, the lovers get to know each other's personalities, and they compliment each other, fulfill the other's needs.... More importantly, passion is portrayed more realistically, w/ real kisses, and acknowledgement of existing desire, that is often absent in K-dramas..... This may have to do w/ the very conservative K-society, although it is not the reality of the existing contemporary S.K. .... China is less prude.
Also, the hero is not always idealized as pure, he is more complex, w/ a darker side, or a more realistic anti-hero ... That said, C-dramas have some of the most amazing male lead characters, that every woman dreams of ... They are idealized yet realistic enough to believe they can exist in RL.
I am not saying that C-dramas are not formula or don't have cliches, or don't have problems... I am saying there are themes, tropes, and subjects not found in K-dramas... and a lot more passion.... So if you want exciting romance, try C-dramas.
--- O.C. I speak in general terms, and my top favorite Dramas are K-dramas ... as I said, there is a reason they are popular.
