Shields are viable but you need multiple slots dedicated to them to be useful. I usually have at least 2-3 slots that are shields. Shield rechargers become a lot better when you have mutiple shields since it effects all shields, so if you have 2 shields that regenerate 1 shield per second each and a shield recharger that increases shield regeneration by 200% you'll have a total of 6 recharged per second. Keep in mind you can have multiple shield rechargers too so you can make shields regenerate quite fast. For examble, at 100 one of my ships has 3 medium shields and 3 shield rechargers for 474.18 Shield regen per second plus another 10 armor regen per second from having armor that regenerates on its own. This, combined with the occasional consumable is more than enough to become nearly unkillable even in level 200 sectors.