hey rito (no disrespect) but I just finished playing a game as nami and man does she feel really useless. I havent seen her played since i started playing wich was like 4 yrs ago. she needs a buff or a change to her e or passive or something cause it a waste to just have her sitting there.
No disrespect, but you haven't had enough time on her to make those kind of statements. Nami is a utility support, but can be played as aggressive as your lane allows. The key thing with her is knowing windows of opportunity and exploiting them.
You have to be consistent at landing your bubbles. Remember her Ebb and Flow is her poke, and when done right can turn trades in your favor. When your adc goes in use it on her or the enemy they are engaging. You can also use it on yourself to bait out enemy skills or for just general poke if you're able. It also is just good for sustaining your lane and keeping you both healthy.
As for Tidecaller, it's useful for procing Nami's passive for speeding up your adc, as well as the added damage and slowing any target they hit. Last but not least, her ult is a solid engage/disengage tool.
Additionally I glanced at your match history. You'll want to take Winspeaker's blessing on her. The keystone you took is more useful on tank supports or supports that have no heal/shield that wish to proc Ardent Censer. Nami doesn't need that, so Windspeakers benefits you and your team greatly. Remember, you're a utility support, not a tank.
However, since that was an ARAM, you can go damage in that mode and honestly do quite well if you know how to handle her kit. A couple examples:
http://matchhistory.na.leagueoflegends.com/en/#match-details/NA1/2614080059/209494370
http://matchhistory.na.leagueoflegends.com/en/#match-details/NA1/2622672860/209494370
Like learning and champion, it's just learning her playstyle and practicing. You'll get there eventually if you put time into her.
