I first encountered Maribelle in Chapter 5 of Fire Emblem: Awakening. She rode on horseback alongside a young mage named Ricken as Wyvern Riders advanced on them. Chapter 5 proved to be the first truly difficult chapter of the game. The tutorial was over, but I didn't have the wealth of options at my disposal that I would later in the game. I wound up restarting the chapter over and over again until I managed to complete it without any of my characters dying. Since I already had a mage in my party, I put Ricken on the sidelines. I needed an extra pair of healing hands, however, so Maribelle found a permanent spot on my team.
As I progressed through the game, I didn't find myself very fond of Maribelle. She was prissy and uptight, often criticizing her team members' manners in their conversations. Instead of wearing protective armor like most soldiers, she was dressed in upper class garb that had no place on the battlefield. Her unusually high magic resistance made her useful, but I had to keep her out of the way in fights, because a strike or two from a bow or axe would have been all it took to reduce her HP to zero. Several times throughout the course of the game, I carelessly left her in a vulnerable position, and restarted the chapter so I could continue on with her.
Character death in the Fire Emblem series is not something to be taken lightly. Unlike XCOM, where there are unlimited characters, and training a new character from scratch is relatively easy, the only characters you gain in Fire Emblem are the ones the story provides you with. Each character has their own specific skills and personality traits, but if they die in battle they're gone forever. Assuming you're playing Classic mode.
I didn't find myself very fond of Maribelle.
Losing a character in Fire Emblem can be crippling, both from a gameplay and narrative perspective. Take, for example, the archer Virion. Not only was his womanizing nature constantly amusing, but his arrows made it easy to weaken an enemy before letting a teammate finish them off. He worked well with the beautiful pegasus knight Cordelia, and over the course of the game, the two characters fell in love. Thanks to some time-travel shenanigans, their feisty daughter Severa also joined my party. These three characters were irrelevant to the overarching story of Fire Emblem: Awakening, but the tale of the family that fought together wound up being one of my favorite aspects of this playthrough. Losing any one of them would be devastating.
Maribelle, on the other hand, didn't have the same impact. She had the odd conversation with a party member now and then, but did not manage to form any meaningful bonds. I tried to build a relationship between Maribelle and the tactician, but the two rarely had time to interact. Maribelle primarily patched up wounded soldiers who had retreated from battle, while the tactician spent most of his time on the front lines leading the charge. Maribelle's healing spells were useful, but as my characters grew in strength, I gained other party members with the ability to heal, making her less important as the game went on.