When you play melee, you are putting yourself in the front line. Therefore you need to be both tanky, and have a way to stay alive. Since you're playing Excalibur, you probably know that melee mods on your weapon also affect Exalted Blade. It is important to note that if you play melee, you're going to be taking a lot of consistent damage, so building Health and Armor is your best option, because you won't be depending on shields to protect you since you constantly put yourself in the front line. You don't dodge damage you TAKE IT. LIKE A MAN.

With all that being said, the core framework for melee builds that I use is Vitality + Steel Fiber + Rage. This makes you much tankier - armor affects the damage you take only to health, so Steel Fiber + Vitality is a good combination to make you durable. Rage makes it so 40% of damage you take to Health is converted to Energy. This, in conjuction with Life Strike, can create a very powerful loop that basically means that you can self-sustain yourself up to very high levels. There are differing opinions on whether or not you should max Life Strike, since maxing it will create a linear increase in what you get out of it and will decrease linearly your efficiency channeling. I believe that maxing out Life Strike is your best option - the trick is to only channel when you lose life. With a maxed Life Strike, you can easily get all of your health back in under 2 seconds. I don't believe that Channeling on a weapon is a good way to deal damage, since that energy is so much better spent on your Warframe abilities. Therefore maxing a Life Strike out means that you can get all your health back when you need it, or in other words in my opinion making every strike count. As a final note, the amount of energy you need to spend channeling to get your life from 2 health to max health is vastly less than the amount of energy you get from Rage.

The above is the core framework around most melee builds, since it allows you to be extremely durable while creating an endless self-sustaining loop. Taking damage to health is actually preferable in some cases, since you can easily get all your health back with the energy you gain. Since you want a fast melee build, I suggest trying Volt. You'll get 2x melee attack speed, 2x movement speed, 5849 effective health, and endless energy since you'll be focusing on casting 2 almost exclusively. I wrote the whole thing here, it's an indepth guide to how the build works. It takes the loop theory a step farther with Quick Thinking, and I think you'd like it a lot, and it recently got a very large buff due to the new melee mods.