1. It's generally pretty realistic. Odds are if you are exposed and that another soldier shoots at you with a machine gun, you'll die. If a NH-27 neko stretches close to you, you might die as well ~_^. If you are on the business end of the weapon used by a NH-28 NIWS, you are defenitely dead.
The trick is not treating the SARP like an RPG in which you have Hit Points and extra lives. When you take risks, they might be the last ones you take, so, you have to exercise caution and make them be worth it. GMs generally enjoy having players participate and do good roleplaying and promote teamwork - usually, as long as you stick by your pals and try to get through a situation by surviving, you ought to be well off.
Medical technology allows to cope from impressive mental trauma, including severed limbs. However, bad things happen even to good characters - even if you do things right, you might die. The Star Army of Yamatai and the Elysian Celestial Navy uses Soul transfer devices to make recording of a person's mind. If the person expires and that she was a valued member of the crew, odds are he/she will have a new body grown and be restored to life, with memories going to up when they made their last backups (so, no remembering death).
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2. About the blades, there are two reasons:
First, Wes likes retro stuff.
Secondly, energy blades in the SARP do one thing those you see in sci fi and anime not do: a shaped blade of coherent energy strong enough to cleave through flesh, bone, wood and metal as if there would be very little resistance would generate enough heat to shrivel the skin and boil the blood of its user.
That's why energy swords are usually reserved to power armor combat (see the Lamia, the Mindy, the Kylie and the most powerful: the Sarah power armor).