Because of that it does feel like her story was late addition especially because there are moments where you can't play as her. On the other hand Milla is a reason for story to begin with and feel more like Estella in Vesperia. Jude gets main plot points because story is about him finding his own place and not being just with Milla. The thing with two story lines is just the difference on who characters are for it.
The weapon system is really simple, you collect different materials by exploring areas and upgrade shops with it, this open new weapons/armors/food/items for buying. The best part of its story is how it ended up in unique way with no bad guys but with a fight between ideas. Players certainly could play the game without linking in a three or four-player scenario, but I feel this would really take a lot away from the battle system.For me Xillia is second best Tales so yes I do recomend it( but I like Arise far more than Vesperia so maybe my opinion won't work for you ). Linking basically has the second character follow the first character’s lead, and begin to auto trigger certain skills and artes based on what the linker is doing.
The reason behind this is that when a character is linked by another character, the linkee can’t really control their character. On the other hand, it effectively makes it so Xillia is best played with two players in co-op instead of three or four. On the one hand, I found it to be extremely fun and add a strategic layer to the game.
The linking system is a pro and a con at the same time to Xillia. This will bring up a table (which can be sorted by character) of all the linked artes they can perform with all other characters, and which artes they need to use to trigger them. Just keep in mind that players can look at their linked artes by going to a character’s artes screen and hitting R2. It sounds extremely complicated, but it’s pretty easy to pick up on and master during play. Mystic Artes are also available only during Overlimit, and must be triggered by special arcane artes. During the time of depletion, players can trigger as many linked artes as they can fit into this time, ideally chaining them together. During this time the bar will turn completely gold and begin to slowly deplete. When the Overlimit Gauge is completely full, a linked arte will trigger Overlimit. Once a linked arte has been triggered the Overlimit Gauge will continue on to the next segment. To trigger a linked arte, the player must use an arte that combos with an arte of their linked partner (so you’ll have to look this up and remember it to make combat run smoothly) then hit R2 when a gold X flashes over their avatar. Once a segment fills up, the X at the top will begin to flash, allowing one linked arte. Players will have to pay attention to the Overlimit Gauge on the left side of the screen, which is divided into about five segments. Linked artes are much more powerful than normal, individual artes, so they can’t be triggered all the time.
The second, and most exciting, benefit to linking is that the linked characters can perform special artes entirely dependent on which two characters are being used (so Jude and Milla get a different set of linked artes than Jude and Elize, for example). Alvin will break guard, Leia will attempt to steal an item). The first is that the character that was linked will perform special actions from time to time on the shared target (e.g. During battle, characters can “link” with another character, drawing a blue or green line between the two.
The biggest change to the combat, however, is the linking and linked artes system.