NO… not because the derv is weak. But some skills should be buffed so as to increase build diversity. Here are my suggestions.
[And yes… I’m spending too much time thinking about this game]
Scythe Mastery –
Lyssa's Assault – This skill might be worthwhile for a R/D…maybe. But for any derv build I can think of its no good. The energy gain is minimal and damage is weak. Changing the energy cost benefits the R/D more than the derv, so that would not work. How about changing this skill to say 5e, and say “If this skills hits, you steal 1…3…5 of target foes energy”. That would also be more in-tune with what Lyssa (ie God of Mesmers) is about.
Reaper’s Sweep – This skill is extremely outclassed by Eviserate. I know you cannot make a direct comparison between dervs and warriors. But this skill sets up that comparison as it is a “spike-pressure” type attack. I suggest changing this skill to say “If this attack hits, you deal +10...34 damage. If your target was below 25…50…70% Health, you also inflict a Deep Wound for 5...17 seconds.”
Attacker’s Insight and Onslaught – I don’t get it. There are no derv skills and few other attack skills that have more than 10e cost. If, as Guildwiki suggests, this is used with Lyssa’s Assault, then you are using two skill slots to gain a net 7 energy ( assuming Scythe is 16). Given that dervs have a decent energy management through Mysticism, this seems to be of little use. In fact, the derv class has several attack-based energy management skills, including Onslaught, Lyssa’s Assault, and Zealous Vow. These skills seem designed for R/D instead of for dervs. But R/Ds don’t need a lot of energy management skills. How about changing Attacker’s Insight to affect the next two attack skills, making it more usefull for Dervs? And for Onslaught, “Elite Enchantment Spell. For 5...17 seconds, your attack Skills recharge 25% faster and you attack 33% faster”
Pious Renewal – The energy management for this is OK I guess. At 12 Mysticism, you get back 6 energy when the enchant ends. The health gain on this is too little. In 8 seconds, you can cast and remove 4 enchants max ( maybe six if you remove them all at once with say, Mystic Sandstorm). So this elite skill can give around 48hp over 10 seconds, in addition to the 72hp from mysticism. That’s assuming you’re who skill-bar is filled with enchants. That’s pretty low healing for a situational, short-lived enchant. As a remedy, I suggest that the healing amount is upped. OR, better yet, change the skill to be like this: “Elite Enchantment Spell. For 8 seconds, whenever an Enchantment ends on you, you gain 0...2 Energy and 0...8 Health, and adjacent foes take 0-15 holy damage”.
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Don't make it like in the preview, but make it worth something ^^