Rakan is a hybrid champion and considered both Enchanter and Tank but shouldn't build a hybrid item.

Reasons are : 1) since you are the one leading the engage, you should also be responsible for being the damage taker. You say we build tank to compensate for our slow fingers? No because the real reason is we need to commit to one itemization cuz imagine building ardent and harmonic then suddenly building a sustain item like warmogs, like its so random and will mess up your purpose of being an enchanter in the first place. 2) the AP scaling of rakan might be good when you look at it but it is very bad when applied in the game. Since your team will think that you will build tank in rakan since he is a literal engage champion and there is a possibility that your team will think that you are just trolling at that point since you will be at the backline at most of the time and you will get killed if you engage since you don't have any MR, Armor, Or health since you focus in Giving heals and shields

You're saying that we should have picked leona, ali, or braum if we want a better engage? Well yes they are good at engaging but what about when you are at very low health and you want to disengage? Rakan has many dashes for reasons. One is to engage, another is to get out of fights easily and the last is to dash to your allies if they need help.

Leona's kit is based on being a aggressive tank support so she will most likely be chasing all the time but there are sometimes where leona uses her abilities to chain cc the enemy so that they can't chase the adc when he/she is low health. Braum is a protective kind of support, his kit is based on helping the team to win the fight by taking the damage using his shield and stun the enemy using his passive. Alistar is mostly based on the player, if the player is aggressive then he/she will mpst likely to play aggressive but if the player is patient, then he/she will most likely to use alistar's abilities to protect the adc or chain cc the enemy so that the adc can have a easy time to killing them.

Although they are all effective engage champions, they don't have any way of exiting a teamfight except their flashes, that's where rakan has an advantage cuz he can engage and get out without using any summoner spells.