So the druid's strengths are obvious at a glance. I'll go ahead and list off its major weaknesses so that your fears might be put to rest.
1. Druid forms have a lot of HP because that is how they tank. Their AC is crushingly low though. That bear form should have an AC of about 11 and their best AC forms top out around 13-14. This means they get hit by almost every attack thrown their way, which in turn knocks them out of form frequently enough that their true HP is still vulnerable if they get focus fired.
So Druids are weak after their forms are whittled down and then focus-fired? That's not a weakness for a full-caster, let alone a major one haha.
Let's add some nuance to the propaganda shall we?
Multiclass dip level 1 Barbarian, or level 1 Monk for Unarmored Defense, and you add CON or WIS modifiers to unarmored AC in any shape. A lowish level Dire Wolf/Monk would have AC 18-19 (assuming 18-20 WIS). An Earth Elemental wildshape (level 10-11), would have 17 AC base + 4 from Barbarian dip or +5 for Monk dip (20 WIS) for AC 21-22 total. Clearly we are not talking about crushingly low AC, but rather strong AC for a Druid who cares enough to strengthen his wild shapes.
5. Their caster form is probably going to have middling AC too. Medium armor... But they can't wear metal. That means no mail or half-plate or what have you. Hide is the best armor they can manage and it is only 12+. So assuming optimized Dex and a shield they're sitting at only 16AC. Nothing ground breaking.
Barkskin (level 2 spell that can be up infinitely assuming it has the Hex/Hunter's Mark treatment) + shield = AC 18...even assuming NEGATIVE DEX modifier.
6. Speaking of AC, being a druid doesn't mean you can totally dump Dex or Con. You need Con to maintain concentration on spells when not in beast form and you need Dex to make sure your caster form's AC isn't abysmal, as you'll likely get knocked out of form at least occasionally. Likely while surrounded by enemies. Strength is an obvious dump stat, but what full caster can't safely dump strength and still be good?
This is at best commonality for all caster, for virtually all non-casters, and not really a weakness at all. In reality though, a Druid has more freedom to dump just about *any* physical stat as wild shape physical stats overrides the Druid's while also having access to Barkskin spell. Having lowish AC (which they arguably don't have) after being knocked out of beast form is again not really much of a weakness. To help further with concentration checks: A level 1 dip into Barbarian would also add Constitution proficiency, while Enhance Ability/Bear's Endurance spell would add Constitution advantage (and more health), or grab Resilient feat.
