So, lots of posts to respond to:
1. Regarding the comments around my not wanting to talk with the DM.
Why? In my experience the best games always involve conversations with the DM.
I dropped D&D a while back and I've spent the last few years playing games that involve cooperative story-telling, so I have no problems having conversations with the DM about narrative changes to the rules. In fact, my group has home brewed most of the D&D we've played - which has ranged from 1st ed to 5ed.
My problem with having a chat with the DM regarding Hallow isn't the actual conversation with the DM. It's the principal. It rubs me the wrong way that that I have to have this conversation because the developers of the game would assume that religions that don't have gods are, somehow, less 'holy' or 'divine'. "sure you can bless my house, but your pagan religion isn't really real, so it won't do anything." I won't get too philosophical here. Instead, I'll quote the PHB again:
PHB:
"Druids revere nature above all, gaining ...powers either from the force of nature itself or from a nature deity. Many druids pursue a mystic spirituality of transcendent union with nature rather than devotion to a divine entity, while others serve gods of wild nature, animals, or elemental forces. The ancient druidic traditions are sometimes called the Old Faith, in contrast to the worship of gods in temples and shrines."
So, somehow the 'Old Faith' is inferior to the 'new faith'. What was it before the New Faith came around? Did it used to be able to make places 'hallowed' but now it can't? That's a cool premise for a campaign but, to me, it shouldn't be the bar. Fantasy is ripe with tropes of 'sacred spaces' that don't exist in temples: Sacred Groves, Ancient Burial Grounds, Protected Forests. Are these not Hallowed Ground? Are you telling me the Iconic Archetype, the one with a 'transcendent union with nature' is unable to protect these 'holy' places or create sacred places that undead or evil are unable to profane? And, even if your definition of 'holy' requires you to have some 'divine entity' that is not 'the earth' or nature itself, or the spirits of nature that are alive in all living things, or "elemental planes and the feywild", the phb specifically mentions that some druids gain their power from a nature deity - druids. Not nature Clerics. In fact, Nature Cleric is redundant, imo.
Therefore, in my humble opinion, Hallow should be on their list without needing to have a heart-to-heart with the DM. After writing all this, though, I realize this is just a pet peeve and probably falls in the category of 'I'll get over it".
I'd love to see a druid a bit more divorced from animal shapeshifting.
Plant shapeshifiting would be neat. Or more plant based abilities and no shapeshifting would be neat too.
Tree shape was a spell that no longer exists. You turn yourself into a tree for 8hrs. Great for spying or resting in dangerous territory
Regarding some of the other spells - like stone shape. They could have made it similar to Plant Growth. Have a '1 action' version that lets you do 5 feet of stone and then have a 10 minute casting time version that does more and allows you to upcast it to higher slots in order to increase the amount of stone you can affect. That would have solved the balance issues, probably. And I will have that discussion with my dm if I ever choose to play a druid.