For paid tickets, a "change of schedule" that allows for refunds, waived change fees, etc., is defined as:
- A 90-minute change in departure or arrival time
- An addition of one or more stops to the routing

If the airline can offer a valid new itinerary (i.e. with legal connection times) that stays within the 90-minute limit and doesn't require any additional stops, then they don't have to give you any other options.

Unfortunately, you can't get a refund if the changes shorten your connections to the point that you're not comfortable with them. As long as the connections are still valid based on the airline's minimum connection times or they provide an alternative legal routing within the 90-minute timeframe, you're pretty much stuck.

I don't know if the same rules apply for award travel, but it wouldn't surprise me if they do.