Well, everyone has their own goals, preferences and enjoys different things.
I don't fly a record-breaker but I prefer exploring sparse areas. So every 0.1 Ly of jump range counts. And I don't really like engineers, have unlocked only four of them so far. And I don't like big ships, I fly DBX now, Phantom and AspX before. So I try to optimize loadout which means dumping useless modules.
Why I consider shields useless? Because, if you fly solo or in PG, they may be useful in one and one occasion only - planetary landings. Do they protect you against the most common explorer's mishaps: emergency drop from SC and faceplanting star/planet in SC? No. You'll damage your hull even if you have the biggest and the most engineered shields in the galaxy. But repair limpets will help you in all of those cases. Moreover, you can use them to help a fellow unlucky Cmdr who has useless shields but has just found himself with 30% hull 50 kylies from the nearest station.
That's why I carry limpets and tiny cargo rack instead of shields.
From the other hand: the discussion is going to be purely academical since we'll have Fleet Carriers in every other system soon.
