I do not know anything about the Waldensians. Specifically, do we actually know what their doctrine was and why the Catholic Church opposed them?
Most information about the doctrine of first valdensians that survived till today is contained in the inquisition protocols. According to "New Advent":
...denial of purgatory, and of indulgences and prayers for the dead. They denounced all lying as a grievous sin, refused to take oaths and considered the shedding of human blood unlawful. They consequently condemned war and the infliction of the death penalty.
are among their doctrines that contradicted roman catholic faith, so I think, that yes, they can be view as sui specie 'protoprotestants'.
Contemporary Waldenses were 'assimilated' into reformation.
Well. Some of what they said makes sense from a Protestant point of view, but not all. The biggest doctrinal "Holy cow I can't believe they said that," is
Holding that the validity of the sacraments depends on the worthiness of the minister (from Catholic Encyclopedia)
This would mean that if your local pastor was shacking up with someone, any baptism they performed would come into doubt. That goes against Augustine's teachings and all (I believe) of the thoughts of the first Reformers.
The Catholic Encyclopedia also implies that they borrowed from the Cathars, which would have put them clearly within the realm of "heretic."
In this book, one curious point is their outright rejection of asceticism. This, of course, goes directly against Christ's statement that certain demons could only be removed by "prayer and fasting" and Paul's allusion in 1 Cor. 9:27 (he speaks of "beating his body.")
There are some things listed here which are concerning (though it is hard to tell which is Cathar/Albigenses and what is Waldenses. Of course, they are interbred). Most importantly:
- Their second error is that all vices and sins are in the church, and that they alone live righteously. (they're sinless?)
- That we are not to obey Prelates; but only God. (Prelates are to be followed according to Peter)
- That the clergy ought not to have possessions (Ask your pastor if he agrees that this one isn't heresy)
- This paragraph just deserves a church-lady, "Well, isn't that special":
Also, they condemn the sacrament of Marriage, saying that married persons sin mortally if they come together without the hope of offspring [this is different from RCC which teaches that there can be no artificial impediment to having children]-also, they disregard compaternity-also, they despise the degrees of affinity, carnal and spiritual, and the impediments of Orders, and of public decency, and of ecclesiastical prohibitions-also, they say that a woman after child-bearing does not require benediction, or introduction-also, they say that the church has erred in prohibiting the marriage of the Clergy, while even those of the East mary - also, they say that the continent do not sin in kisses and embraces.
A bit of a side note: it seems that the first and foremost reason they were condemned was that they did not submit to the local authorities. They were instructed to visit with the bishop (who, at that time, was a lord) and they refused. When this obstinacy continued they were de facto criminals endorsing criminality (if you are summoned to court, you go to court. God does not give us free passes to get out of traffic tickets). Once they were condemned for this behavior by the local synod of bishops (a synod represents a small geographic area), their doctrines started to diverge from Catholic (and I would argue eventually even what could be passed as Christian) thought.