I have the following use case and i am wondering if it is possible today:

Customer generates a ticket, they set a custom field to: Problem Type: 1 - Severe.

Internally, i have another field that set's which tier/group should handle this ticket on creation. I want to be able to say things like: 

if ProblemType IS 1-Critical, set Tier to Tier2

else set Tier to Tier1

So a simple if/else structure. The second part of my question is - can i do if/elseif/else structures? Like the following:

If field1 = X set fields1, fields2

else if field1 = Y set fields1, fields3

else if field1 = Z set fields2, fields3

else set fields1, fields2, fields3

Are either of these two use cases possible WITHOUT creating multiple rules?

So far as I am aware, FreshService doesn't support any logic more than filtering and applying.

So multiple rules is the way to go if you want to keep it in the box.

More and more, we have our tickets reviewed by our own service against the FS API and update things accordingly, with our external logic being as robust as we would like.