I’m sorry to hear that the host seemed to have outright lied about the plant care responsibilities. 60 plants and trees certainly does not qualify as a ‘few.’
But once a sitter has been ‘burned’ with a particular situation, especially more than once, even if it is a situation that is unlikely to be an ongoing occurrence, the best they can do is ask hosts directly about the issue, which is what you did.
Unfortunately in this case you encountered someone dishonest, but for the most part, I think that the vast majority of hosts are forthcoming about responsibilities, especially if asked directly about something.
If more involved gardening and plant care is one of your ‘dealbreakers’ you might ask about this right upfront in your application message, asking hosts if they require any sort of care in this regard, and to tell you specifically the amount of plants and the time it typically takes to do the job.
I have gone to a few sits that ended up having a good deal of indoor plants and it did take up some time. But it is not something that is so concerning that I feel the need to ask about it specifically prior to confirming; also I doubt it was something they deliberately did not mention. For any sit that had a particularly involved amount of plant and garden care, those hosts have always told us about it upfront.
As for the suggestions you mentioned, plant care info could be helpful.
But the one about rating the value vs the responsibilities would not be as helpful I think. While all the rating categories are subjective, this one is particularly so.
Some sits have more involved responsibilities, especially in regards to the home, and depending on the person, and the specific requests, some may not mind that at all. They may even enjoy doing those things.
For example, my husband and I have a lot of free time and some of these more involved tasks do not bother us–it can even be nice to have some stuff to do to take up the time. But another sitter who may have a busier work schedule or wants to spend more time exploring, would not find the same sit as appealing.
The reviews are somewhere that someone can mention specific tasks that are required for the pets, home,etc..–and it can be done in a neutral way of just stating a fact–and this info can help future sitters know if it is a good match or not.