Manga canon has the Senshi except Moon all die in practically every arc. They've been stabbed, slashed, shot, strangled, exploded, mind-raped, mind-controlled, and disintegrated before being brought back as magical zombies. Then Moon brings them back. From a strictly ruthless point of view, the Senshi were practically guaranteed a win every time; the tension is in the fact that these are characters not RTS units, and they still felt pain and trauma, both emotional and physical. The inner Senshi in particular, become more and more psychologically dependent on Moon as the series goes on. Near the end, Venus was still talking about boys and hanging out; she was told to drop the act whereupon she seriously confessed that she'd already dedicated her life to someone cough*Usagi*cough.
Mid-Bosses, even when they were rival Senshi, rarely lasted more than a couple of chapters. The body count in the manga is staggering; the Senshi defeated or killed, directly or indirectly, something like forty named villains over seventy chapters.