I think the 2nd item is really the core issue. Most people here agree the Rogue's conceptual niche is/was the skill monkey. But with the aforementioned skill issues in play, the niche isn't a niche. If degrees of success mattered, then maybe an extra +2 to +4 would be more impactful; or if the dice being used were different (multiple dice - even 2d10 instead of 1d20 can make extra bonuses vastly more interesting). For example, replace skill check d20s with 3d6. Now generally only a skilled person can achieve a 20+ at all. Or, like Pathfinder, gatekeep certain results behind skill level not total bonus. I love this, and try to soft-implement it in all my games. The +4 DEX Fighter is good at hiding behind walls (+4 to Stealth checks, untrained), but even the most novice Rogue (+0 DEX, +1 skill, TRAINED) is better at tailing someone (Stealth check, MUST BE TRAINED or better). But again -- we (5e) are trying not to penalize the party for not having a specific class...
I really liked D&D's only attempt at this in a previous edition: anyone can (try to) disarm a mundane trap, but you need a Rogue to disarm a magical one. [Even then, along comes the wizard with dispel magic.]
Making level of skill and value of bonus would go miles towards putting the Rogue back into the niche. Even if the bard has the same Expertise, the Rogue's class abilities should make the skills better in her hands. Even if the wizard is using knock and invisibility, the Rogue's class abilities should make her lockpicks and stealth better.
(I also loved the idea to give the rogue more ways to apply their skills in combat. I'd caution against the dangerous Battlemaster-style 5e mindset ["Since Trip is a battlemaster ability, I guess you can't trip without being a battlemaster!"] But I'd love to see combat tricks and techniques that take their out-of-combat skill and apply it creatively in combat. And yes, the 5e subclasses do this a little, but more can be done in this area. Laserllama's Maneuvers for martials, or Pathfinder's feint and demoralize actions, players just asking to errol-flynn-chandelier-ride across the field... all good starts.)