For your question about Resto Shaman, the driving design intent was to make a healing set bonus that felt fundamentally like Resto Shaman. Chain heal and totems are very core Shaman spells. While Chain Heal has fallen a bit out of favor in Shadowlands, this is due in part to how Legendaries and Covenant-related systems have altered the healing-per-mana of Resto Shaman spells. From a design perspective, that means there’s an extra roadblock to making a cool Chain Heal set bonus, but it doesn’t necessarily mean Chain Heal is off the table.
The first iteration of the resto shaman set bonus tried to build an engine around Chain Heal and Spirit Link Totem, but in addition to specific spirit link timing concerns, that would have had the issue of either pushing Chain Heal to the front of Shaman heals at all times, or not being enough to overcome the HPM concerns and ending up unused, depending on how tuning worked out. So we moved towards a bonus that builds an engine around critically hitting, which synergizes with the core mechanic of Resurgence, and rewards you for casting Chain Heal some amount of the time.
Broadly, players understandably look at set bonuses through the lens of how they’re currently playing the game. Sometimes a designer is trying to accent part of their class’s identity that has fallen out of favor, rather than something that already feels important to them. That distinction can lead to that ‘disconnected’ feeling. But ultimately, we all hope for the same thing in the end - fun gameplay that resonates with our class’s core fantasies.