Hey Brodie,
seems like a number of us new Kaleun's have had the same experience (seeing the screenies prompting impulse buy of discount-bin SH5).
I've tried TheDarkWraith's Magnum Opus mega-mod + his New UI mod but stopped using it because I found the AI too rigorous for my taste (I've since discovered that they can be toned down to be much less aggressive). MO is a comprehensive mod pack and well worth giving a try.
I've currently using Obelix's AVC 2 mod pack and really like the way everything is presented... more "period" than MO, but it's a matter of subjective taste. I'm not into very high difficulty settings, so perhaps try AVC first and see how you like it.
I haven't tried up Open Horizons yet (I want to give the stock career a full run-through first) but it looks like another "must have" on the mod list to me.
Other than that, I like the Critical Hits mods for torps and guns which, to me seems to implement a more realistic range of torpedo and shell damage. The nice thing about JSGME is that it's fairly easy to come up with one's own "mod soup".
Happy hunting,
C_G