I believe that we would all agree that women should not attend church in hot pants or a bikini. I'm just not sure if that is exactly what Paul was dealing with in 1 Timothy 2 (or Peter in 1 Peter 3) or if this type of indecent apparel was a big problem in the First century churches. My only question is, maybe the Apostles were dealing with the problem of ostentatious and immodest display of riches on the part of some church members.
"Too little clothing" was a marker of social status, not indecency. Slaves routinely wore short tunics or loincloths--it was seen simply as a necessary and suitable garment for their kind of labour. Conversely, prostitutes were required to wear togas.
The basic Roman garment was a
tunica--basically a long shirt that reached down to some point below the waist. It was pretty much a rectangular piece of cloth with a hole for the head, that was open at the sides and tied with a belt. Wealthy or upper-class women would also wear a
palla, a shawl that also covered the head, and married women wore a
stola, which was an outer sleeveless robe.
Certain clothing was also a social requirement. A male Roman citizen was required to wear a toga in public, and a female citizen wore her tunica, palla, and stola. It would have been a social disgrace for a high-status man to walk around in just his tunica, though that was appropriate for a tradesman.
I don't believe Paul was writing against wealthy people and citizens wearing expensive clothing that was appropriate for their social status. On the contrary--his teaching on head coverings in 1 Corinthians seems to reflect Roman values on the subject: it was shameful for a respectable woman to go in public without her palla and stola, and it was an offence to harass a high-status woman so dressed. Those garments were her dignity and her protection. It was a disgrace for her to go without them--it marked her as sexually available.
There is an immodesty of "too little," but also one of "too much." Cloth was an expensive luxury item, so how much cloth a woman could drape over her body was a sign of wealth. Clothing was a literal status symbol, and it was possible to be
too showy with their garments. Women would also spend a lot of time and money on jewelry and elaborate hairstyles to complement their outfits, doing things like weaving gold filigree, pearls, and jewels into their hair. And then they came into church and sat next to lower-class and slave women who could never attain to that kind of conspicuous wealth.
So Paul would want the women of the church to dress appropriately for their social status, but not more elaborately than necessary, which was just immodesty--showing off.