You have eight characters by the end of the game, and can fight with a party of four. Star Ocean: The Last Hope has perhaps the best action combat system in a JRPG. If gameplay is the most important part of a game for you then I have excellent news. The ability to use the ship to travel freely between world near the beginning of the game is much appreciated, and adds a freedom not found in previous entries in the franchise.
Sidequests can range from killing a monster to delivering item orders for a shop. The game can be beaten without ever really straying off of the main path, but some of the side quests can be fun and make use of your crafting abilities.
Some planets are pretty small and linear, but others are full of sidequests and potential exploration for the determined player. Most of The Last Hope's gameplay is spent using your ship, the Calnus, to freely travel between a handful of planets. There is enough between the character interaction and the plot to keep the player going, but thankfully The Last Hope has a lot more going for it than its narrative. That said, the game clearly tries to find a deeper message than it really has to give at the end, and ends up being wordy without really saying much at all. It at least avoids a horrible end-game plot twist like its predecessor used to try and gain attention. The plot itself isn't particularly bad, just very predictable. Some of the character interaction is good, although there are more cringe-worthy moments than genuinely good ones. Edge spends a few hours halfway through the game being an incredibly annoying and depressed prick, and right as he manages to come out of it another crew member decides to make himself the most annoying character in the game.
Often characters will actually regress in maturity. There is nothing extraordinary in the plot, and character development is poor at best. Eventually the inevitable great evil threatening the whole universe pops up, and Edge and crew set out to stop it. Along the way Edge and Reimi meet the expected anime cliches (the cat girl, the android, the annoying child, the disgruntled badass, etc.) and continue their travels with their ragtag crew. Together with his childhood "friend" Reimi Saionji, Edge travels space exploring new planets for potential human colonization. Enter Edge Maverick, a seemingly average young pilot in the SRF (Space Reconnaissance Force) with an inferiority complex.
In the year 2064 the Earth almost destroys itself in a massive nuclear world war, forcing humans to begin searching for a new home in space. This would matter more if Star Ocean plotlines were even remotely related to each other, but as it is you don't need to know anything about other Star Ocean games to play this one. Star Ocean: The Last Hope is chronologically the first story in the Star Ocean franchise.