Until they change things, I believe Wu Kong is a hero worth building an entire team around ( see notes )
I am a huge fan of 4* 4.70 Melendor, Grimm, Scarlett, Wu Kong, Rigard ( see notes ) as a first rainbow 4* 4.70 team. It can autoplay most things and gets great titan scores. A little weak in war, but that is were 4* 3.60 heroes shine since they give you versatility while two 4* 3.60 cost the same Hero XP as one 4* 4.70.
I actually have a second Melendor, Grimm, Wu Kong and Rigard at 4* 3.60 in addition to my 4* 4.70 ones, but that will depend on you play style and summons. I love your roster of 4* red heroes.
It costs a lot to raise a hero to 5* 4.80 ( see notes ).
Especially with the coming Classes update, some players are going to decide to expand their roster of 3* 3.50 heroes and 4* 3.60 heroes.
==Second 4* 3.60 rainbow==
Proteus is a great special skill control hero ( unlike Hansel/ Merlin/ Gretel, Proteus effects multiple targets). Eventually you will want Proteus at 4* 4.70 but works fine at 4* 3.60 until you get more 4* 3.60 heroes leveled.
Jackal is a super glass cannon. His attack stat is the third highest yellow, only two yellow HotM are higher. So even when he is dead, he increases your match/ board/ physical damage. He is the only Elemental yellow defense debuff hero. This stacks with rainbow elemental debuffs like Ramming Pulverizer making Jackal amazing. You will eventually take Jackal to 4* 4.70
I am a big fan of 1-2 healers and color stacking. Kiril is a good healer, that can be tricky to use since his healing is only 28% and his free dragon banner only lasts 3 turns. However in war you only need so many Rigard ( 42% heal and cleanse ). Kiril can remove an enemy attack debuff ( ex: enemy Scarlett or Skittleskull ) and an enemy defense debuff ( ex: Ramming Pulverizer ) by overwriting it since only one rainbow attack modifier and only one rainbow defense modifier can effect your team at once. I swap him in for my Rigard versus Vampire Lords in rare quest to get the Royal Tabard. My Kiril is still 4* 3.60 and works well there.
Caedmon is a fast mana speed, green sniper and 4* green is mostly strong in defense so he is a unique 4* green right now. Eventually you will supplement him with Hansel and Peters if you get them ( I love my Hansel 4* 3.60 and will be leveling him to 4* 4.70 ). No battle item removes enemy buffs, so a fast dispeller is always useful in you roster. Fast snipers are very useful in war. My Caedmon is still 4* 3.60 and works well there. A lot of the original generation 1 heroes are being replaced by better challenge event, seasonal event, and Atlantis heroes ( Peters than Hansel ). Due to families, we expect more 4* Atlantis heroes and their are rumors of many more Atlantis 5* heroes.
Boldtusk is very similar to Kiril. His attack buff can overwrite an enemy attack debuff ( ex: Scarlett or Skittleskull ) in war. Boldtusk used to be an effective 5* Heroes but has been repeatedly nerfed until actually a 4* hero. I use him similar to Kiril. His attack buff is also great for farming 1.12-9 and uncommon/ rare quest.
My Boldtusk is still 4* 3.60 and works well there.
==Third rainbow 4* 3.60 team==
Sabina is basically a purple clone of Melendor. Melendor + Rigard work well with Wu Kong because they gain mana from different colors. This is especially important when using auto play on normal difficulty of season 2 map. But Melendor is weak against Red Bosses ( Sabina is neutral ) and Sabina is strong against Yellow bosses. I actually have two Sabina at 4* 3.60 because her 42% heal and dispel is very useful in war and color stacking.
Chao? I keep trying to level my Chao but keep getting better heroes like Jackal and Joon. I still plan on raising him to 4* 3.60 for war and the rumored class update. Not sure I will ever level this majestic raptor, and his pet human, to 4* 4.70.
Sonya is a more defense oriented version of Caedmon ( she has higher defense and HP to his higher attack). Useful against Red bosses ( Caedom is weak and Sonya is strong ) and rare red titans with reflect damage special skill. My Sonya is still 4* 3.60 and works well there.
Little John is a group mana control hero which is always helpful. High attack stat for matching/ board/ phyisical damage. Glass cannon so benefits from 1- 2 healers on the team. Green attack all enemies is awesome for farming 1.8-7 for recruits.
Wilbur is like Wu Kong, a hero worth building a team around
==Fourth rainbow 4* 3.60 team==
Hu Tao yellow attack all enemies is useful for farming 1.8-7 and common quests. Hu Tao’s blindness can be useful in war, but Hu Tao is really a niche hero. Especially with Jackal, I would recommend leveling him to 4* 3.60 and leaving him there. Another generation 1 hero out performed by the glass nuke of Wu Kong and the super glass cannon of Jackal.
Valeria? Damage Over Time bypasses the defense stat so useful against high defense enemies in war. Steal healing useful against enemy healers and Field Aid ( WR ). Very fast mana especially helpful in war. I am leveling my Valeria to 4* 3.60 so you will have to ask others how effective she is in war. But I like my Perseus 5* 2.60 ( only 1*/ 2* ascension materials ) when using Perseus in war against war defense team healers.
Falcon take to 4* 3.60, for now. Eventually you will want to take him to 4* 4.70 but Boldtusk and Wilbur are just so useful for everything so I would level, and play with them, first. Falcon makes a unique second red due to his Elemental red defense debuff ( like Jackal, but multiple targets ) and his high defense stat. Only one, or two, red HotM have a higher defense stat. Since defense is not linear this is impressive. The upcoming Classes will weaken him in relation to 5* heroes, but his Elemental red defense debuff is still worth it.
Between reflect green event, and Atlantis summons, probably more 4* heroes. So by the time you get to your fourth rainbow 4* 3.60 team, you might have other purple 4* and green 4* hero to level with this team.
==Yearly Hero XP==
You can raise 2- 3 rainbow 5* teams per year, -OR- 4- 6x rainbow 4* 4.70 teams per year -OR- 8- 12x rainbow 4* 3.60 teams per year from training camps alone.
So leveling two, or three, rainbow 4* 3.60 teams, then raising five heroes to 4* 4.70, then leveling two, or three rainbow 4* 3.60 teams, then raising five heroes to 4* 4.70, then leveling zero to two rainbow 4* 3.60 teams will give you 20x 4* 3.60 heroes ( the most powerful in the game with 1*/ 2* ascension items ) and 10x 4* 4.70 heroes ( the most powerful in the game with 1*/ 2*/ 3* ascension items ) and consume roughly a years worth of training camp results.
Thirty 4* 3.60/ 4* 4.70 heroes are a good base for war, and classes, and by then you will have all the 4* ascension materials needed to start leveling your 5* heroes. You may even have better 5* heroes at that time.
==rainbow 5* 2.60 team==
I am a big fan of trying out 5* heroes at 5* 2.60. Once you have a rainbow 5* 2.60 team you like, you can raise them to 5* 4.80 which will consume twice the 3* ascension items, and 212% of the Hero XP of a rainbow 4* 4.70 team.
By this time, you may have even better 5* heroes then you currently have.
Between a rock and a hard place!