Inspired by EqD's Artist Training Grounds challenge, this isn't technically a suit of armor, nor does it look all that interesting, but I feel I need to catch up on drawing living things rather than machines.
The Magenta Ranger facing off against Nightmare Moon alone, while the others are busy crushing the Shadowbolts and their machines. Of course, it doesn't go so well.
The idea for this part was that Twilight still didn't experience the Spark at this point, and as such has no Titan (giant robot) form, and gets her plot handed to her in one-on-one combat against Nightmare Moon. The Rangers arrive to help her just in time, beat back NMM, who then goes Godzilla on them. Seeing her friends rally to her, Twilight experiences the Spark and activates her own Titan form, subsequently forming the ultimate Harmonic Titan Megazord and pulverizing Nightmare Moon. Beaten, NMM surrenders her power and releases Celestia, turning back into princess Luna. Etc, etc. It'd really make a fun comic or story if I had any talent for drawing comics or writing.
I'm prepared to chip in my writin' powers if you're willing to use my words.
I'm not really seeing anything wrong with this picture, aside that her tail seems to be curving inwards.
I know it's not the best but it's the best that I could do.