What type of key puller did you use?
It doesn't look like the broken part messes with the function. Most people strike the enter key on the left side. If I were in that situation, I might glue some shard of plastic back on, if it did change the feel for the worse.
It's difficult to remove the MX stabilizers on any of the long keys on a Majestouch without desoldering all switches, except for the spacebar's (since it's at the edge of the PCB and you can slip in something under the plate to press one of two snap tabs that hold a stabilizer clip in place). You might be able to destructively remove it but that would have unpredictable results, and puts you in a worse situation...