Crockpot garlic veggies - something missing?

I'm trying to find a vegetarian recipe that Stefan likes - not just tolerates, because I've worked on it, but wants to eat. He doesn't have to love it - I just want to hear, "Yeah, that's good" when he finishes, and he'll like it enough to get seconds.

He claims that he can be satisfied with a meatless meal - even though he never has been satisfied with a meatless meal. He'll eat them, but no matter what the meal is, he will say, "Something missing." I'll respond, Meat? He'll assure me that it's not meat, but it is something. 

Here was my latest attempt to create a really hearty vegetarian meal. I based it on a chicken dish I make that is my current signature dish. I thought I had hit it out of the ballpark - it's the best vegetarian dish I have EVER prepared, and I couldn't get enough of it. I thought it was absolutely delicious. I thought I'd finally made that meatless meal Stefan would like. 

But Stefan again said, "Something's missing." And he ate just one, modest serving.

Crockpot garlic veggies, to be served over rice or noodles
Feeds 4-6 people



Ingredients:2 yellow squash, sliced
1 can green beans
1-2 onions (to taste), sliced or cut in rings
2 yellow or red peppers, sliced or cut in rings
200 g sliced mushrooms
4 cloves garlic, minced
2 teaspoon dried Italian seasoning
1 teaspoon salt
1 teaspoon cracked black peppercorns
1 cup dry white wine
2 can tomatoes in juice
1 tbsp olive oil 

1 tbsp salt

1 tbsp Better Than Bouillon vegetable base
Optional
1/2 cup sliced pitted black olives  
1/2 cup sliced pitted green olives  
Finely chopped Italian flat-leafed parsley
1-2 bay leafs


Optional pre-cooking
Stir fry onions on medium, until softened, about 3 minutes. Add garlic, Italian seasoning, salt, peppercorns, wine and cook about 1 minute. Put aside.

Cooking
Arrange all veggies and mushrooms over bottom of slow cooker and cover with everything else (or sauce you've pre-cooked). Cover crackpot and cook on low for 7 hours or on high for 3 hours. Discard bay leaf.

Serve
Serve over rice or noodles
Feeds 4-6 people

Note: May not be salty enough for everyone's tastes. Encourage guests to salt to taste. 

So, other than maybe substituting chicken or beef bouillon - which will mean it's no longer vegetarian, but it's close - what could I do to make a meat love like this, without actually adding meat? BTW, he does not like egg plant. 

October 3 update:
Stefan says adding hot sauce made it much better, in his opinion. But he still isn't crazy about it (he'll eat it, but not ask for seconds).