I'm not an expert, in fact I've raided a little on this tier as Boomy but went on hiatus for a while. But I can share this feeling, as I've been playing this spec since BC and seen many different phases of it. I can say we have had some significant development and have had answered some of our concerns during Dragon Soul itself (less Eclispe downtime, less clunky Starfall handling, less tought when using DoTs, more CDs to burst), but on doing so and adding the whole talent revamp, we actually got a messy spec and some mechanics that collide with the design(?) of it.
Just because boomys can pull good dps doesn't mean it's not extremely clunky. There are a lot of things to deal with as a boomy that can be very frustrating.
Movement, natures grace uptime, on demand aoe, and CD timing are some of boomy's biggest concerns. Movement dps is really, annoyingly awful compared to most other range (Spriest feel some of this pain) and lost time on nature's grace between eclipse can be devistating.
The whole lack of interesting glyphs is a minor thing imo compared to boomy's biggest issues.
Just to explain a bit further these concerns from the PvE-side, focusing on the class without any other Tier and such:Movement:
We can deal with this using Shrooms/Detonate and Lunar Shower. Now I'm pretty sure LS has a disadvantage (pertaining to all DoTs actually) which is spamming Moonfire/Sunfire, which by default refreshes the DoT with the snapshot of the Spellpower, Haste, Crit and other buffers you have (Eclipse, CDs, Trinkets, etc). While the buffers are active, this near-zero mana cost spam is useful... until the buffers are over and you start risking on refreshing the damage of the DoT with less and less buffs.Nature's Grace Uptime:
The problem is not the buff, but how to keep the uptime on it. To transitate from Eclipse to Eclipse, you have to succesfully cast Starfire, Wrath, Starsurge or channel Astral Communion which during it you deal 0 damage. In movement, we only have RNG procs from Shooting Stars. So we have to use 3 standstill casted spells and 1 instant-cast RNG proc to move the bar ASAP to the next Eclipse or we lose the NG buff.CD Timing:
Moonkins, baseline speaking, have a cooldown (Celestial Alignment), plus a possible 2 extra ones through talents (Incarnation: Chosen of Elune or Force of Nature @60 and Nature's Vigil @90 if we talk about damage CDs).
I'm going to focus on the most prominent combination of all since FoN as a CD is not very competitive damage wise and does not stack multiplicatively with other buffs/CDs... Which leaves us with CeA+Incar+NV (Not used all 3 at the same time, but under a 30-sec opener). This actually makes us 3-min wonders on a 30 sec sequence, but as you know, we offset this with lower power the rest of the time. On one hand, having CDs helps us to deal with bursty situations, but the current stacking we do is way too damage-heavy and that actually hits us in a myriad of ways (having a sizable difference in our damage depending on how many times we can use the opener rotation, for example, plus movement that starts under the 30sec mark).On-demand AoE:
This issue is tied to Nature's Grace too. To do AoE, we have Hurricane (AstralStorm in Lunar Eclipse), Shrooms/Detonate, and couple that with Moonfire/Sunfire multidotting and even Starfall (although I wouldn't call those AoE anyway). Still, our greatest AoE damage is tied to Hurricane, a channeled AoE but does not produce Eclipse Energy, so when it comes down to rush to the next Eclipse (and keep NG up), you are still tied to the single-target rotation or use multidotting and get SS procs to hasten up that transition.
Possibly some of these points mentioned are the "Challenge of mastering a Balance Druid". I can't actually shorten the post more without hiding relevant information about the "issues"... heck, some of them might even be within the sought-after design of the spec, but I digress.
Now that the design as it is feels clunky when put into real encounters (T14 as of now), it's something that can be considered too as feedback.
I think we just lack some QoL fixes and more synergy with the talent tree itself (feels so... alien from the base rotation itself), not just mindless stacking of spells.