Greg... that is what evolutionists taught years ago, and it seems some STILL believe that.
Geneticists rarely, if ever think there is such a thing as a truly neutral mutation. Virtually all mutations are thought of as VSDM's (very slightly deleterious mutations). In human genomes, each generation has about 100 or more (possibly a few hundred) VSDM's and about 3 deleterious mutations added to our genome each generation. Every human has a few thousand deleterious mutations in our genome. Selection of course is incapable of detecting and removing mutations in a population (as in all primates) where there is a high mutation rate and low birth rate. These accumulating mutations have been referred to by geneticists with terms such as 'the population bomb'. The accumulation of VSDM's (genetic load) leads to further eventual genetic problems in the future. (Genetic disorders and diseases will increase.
Evidence from genetics is consistent with the Biblical model. Evidence from genetics is opposite of what the common ancestry model needs. Geneticists (secular ones) understand the problem and there are numerous articles in journals where they propose various models attempting to make evidence fit their beliefs (multiplicative model, synergistic epistasis, additive model).
BTW... "good mutations" you refer to is essentially a fantasy of evolutionists from the past. Even for geneticists who think there is such a thing, they still know it is so rare that it isn't used as a solution to the 'population bomb' problem. The so called 'good mutation' is considered so rare that it does not show up on charts where geneticists graph mutations. Graphs generally show most mutations as "near neutral", then tapering off towards deleterious. They don't chart any mutations on the opposite 'good' side of the neutral line. Yes, there are some rare mutations that have beneficial outcomes, but usually resulting from a corruption of information. For example the CCR5 mutation results in HIV resistance, but even secular literature calls this a "defective allele of this gene".. which can result in the person now being more susceptible to West Nile and hepatitis.