My issue is that both 3e and 4e had some kind of mechanical process for many of these aspects of the various iconic versions of rogues in the PHB.
It's understandable, but there's a solid reason 5e DOESN'T have that kind of procedural detail: bigger, more meaningful decisions are smoother in play. Rather than being "the guy who can travel an additional 5 ft. when pole vaulting," the rogue is "the guy who can achieve feats of acrobatics beyond others" (thanks to expertise), which may include extra pole vaulting feet among other things (I imagine the DMG rules for setting DC's will be good at revealing the intended in-play distinction between expertise'd and non-expertise'd folks, as there's 2-6 points of difference between the two). Players and DMs are encouraged in most places to make bigger choices than if one specific use of cunning action can grant another moment of combat advantage (that is now redundant with the fact that someone else is in melee with the enemy anyway).
If more fine granularity is desirable for you, it might be more fun to stick with 3e/PF/4e, as those lineages definitely care about those details.
So 5e should have followed the example of past editions in the 5e way. Unless the 5e way is "ask the DM for a house rule and refluff".
There's a few good reasons why 5e cut ties with the particular detail of the two previous editions (one of them that springs to my mind is that this detail encourages "pixel bitching" over fiddly bits). The "5e way" is still being felt out, but it seems to sit well above dictating very specific skill results, encouraging instead a use of skills that is more interpretive than definitive, which in turn allows for more individual variation to emerge.
Part of what that means is that DMs take a more active role as judges than in 3e or 4e (where the detailed rules often served that function). Which in turn means that the social aspect of the game -- talking to your DM, communicating about intent, understanding each other -- is highlighted.
I just find the fact one of the most variable classes of the last two editions has only 3 subclasses and one is "cast wizard spells". Can't even feint or sly flourish without DM adjudication anymore whereas we get green knights and trickery clerics.
Again, I think it's key to think about the results you want more so than the specific processes. What did adding your CHA mod to damage via Sly Flourish
functionally do in play that made it fun, and can you find that fun in 5e even though it doesn't use that process?
It might be that the process itself was part of the fun in which case 5e's simplification of that process is not gonna be up your alley, I think.
It might be, for instance, that the functional element of Sly Flourish was that it made your CHA-focused rogue a competent melee combatant, thus encouraging you to have a high CHA and removing the pressing need for being a DEX-exclusive demigod, which played to the idea of a charming, deceitful character.
I think 5e does that latter thing. Bounded accuracy means that you don't need a DEX of 20 to be a competent melee combatant, thus allowing you to pump up CHA and playing to the idea of a charming, deceitful character. It does that without having to add CHA to your damage.
Feinting might be seen in a similar light. If the functional element of it was to give the rogue more options to get Sneak Attack off, 5e can do that without worrying about embedding a rule in some corner of the skill system.
So I think the 5e rogue maintains and even expands upon (thanks, bounded accuracy!) the variability of the 3e/4e rogue, without getting buried in minutiae. O'course, one man's minutiae is another man's treasured mechanical process, so I'm not here to argue that it's better.
Just that if what you're interested in is the result, rather than the process, you can still likely achieve that.
I say this as a person with a lot of experience doing this in 4e, though, so maybe I've got a high threshold for it. One of my currently played characters says genasi swarm druid on the tin, but is played as a druid who turns into rainfall. The result of "druid who turns into rainfall" trumps the process of building her as a genasi swarm druid with an encounter power that is a close burst 1 that provides concealment. The important thing to me is how that power supports the story I tell, not the power itself.
I mean, this is a lot like folks who, with the advent of 4e, said they couldn't play an archery-based fighter. If you wanted the process of a fighter with a bow, no, you couldn't do that. But if you wanted the effect of a skilled archer, you could totally do that (it was called "ranger," and there's some good role-driven reasons they didn't stick it in the fighter class). Now with the advent of 5e, you can't play a rogue who adds CHA to attack rolls, but you can still get the effect of a charismatic rogue because that story trumps the specific mechanics used to embody it in 4e.
