So what is it that has enchanted me about this franchise so? Well the most obvious thing is that I'm already a big fan of mecha, so I am being marketed to pretty directly by this franchise, but beyond that, there is something special and charming about the series. It's taken me a lot of time to really nail down what exactly I think that is, but I'm gonna give it a shot here and now.
The first thing that's going to hit someone playing these games that might endear them to the franchise is probably the music. Most SRWs have an immediately banger theme on the title screen, especially after JAM Project joined the series. Then beyond that, the games all have their own renditions of classic anime tracks from each series represented, usually the openings, with a few exceptions. In the modern era where file sizes and audio channels are non-issues, there are premium music packs that are the literal versions of the openings, with the lyrics and all that, as well as a feature allowing custom music, so you can really have whatever kind of musical experience you want. The tracks change for big moments and on each attack, which lends a real sense of excitement to what is otherwise just... a very long version of the average Fire Emblem attack exchange.
The animations themselves are something of a fascinating evolution for the series. In earlier games on weaker hardware, animations were fairly simple most of the time. a sort of "move and shoot" anmation pattern was common, with only a handful of "signature" animations specific to some robots. This was complimented by equipment systems where you could edit the weapons on a majority of the units, moxt exemplified by the Original Generations games, which are all original robots instead of mostly being anime characters with all their licensing restrictions.