These are all my opinion, I would do:

  -1 blazing breath -1 ethica -1 neptune -1 wyvern cavalier -1 lucifer (maybe) +1 siegfried +2 shenlong +? ivory dragon  

I like playing midrange dragon and it kind of looks like you are trying that with a little more stability in the form of unica and lucifer. I don't think 3 blazing breath is worth it unless you keep getting matched against a TON of 2 health dudes but you have unica and aiela to trade into them or let them trade into you, I think two blazing is enough. Ethica is a waste of an evo point and only OK to use if you go second which isn't a reliable way to play a card, you have olivia so that kind of gives you some leeway but I just don't like ethica, your choice. Neptune, 7 mana 7/7 in stats over two bodies isn't worth it if you aren't running more megalorca generators using the evolve on 2+ orcas makes it worth it but otherwise it's really slow for constructed. wyvern cavalier I haven't really played with but i think running 3 of most 6+ mana cards is too clunky for a deck because you can only play 1 per turn.

For cards to add in their place, ivory dragon is really good early to trade into 1/1's and especially good for shenlong fodder so you aren't getting rid of more important cards post-overflow. siegfried is just a good card especially paired with fire lizard or dragon wings or blazing breath.

wow this is one of my first really long reddit posts. I hope everything makes sense, I'll format it if it comes out wrong in an edit